ENGINE ELECTRONIC SYSTEM INPUT / OUTPUT COMPONENTS OF CONTROL SYSTEM … …… … … … …E-2 WORKING MODULE TABLE OF FUEL INJECTION / IGNITION SYSTEM …E-3 WORKING PRINCIPLE … …… … … … …… ELECTRICAL CONTROL UNIT …… …… … … … …… …… … … … …… …… … …E-4 …… … …………E-5 WORKING PRINCIPLE OF ELECTRONIC FUEL INJECTION CONTROL AND ACTUATORS …………………………………………………………………………E-7 BASIC PRINCIPLE OF MALFUNCTION DIAGNOSIS FOR ELECTRONIC FUEL INJECTION SYSTEM ………………………………………………………………E-21 DETAILED TABLE OF MALFUNTION DIAGNOSTIC CODE
INPUT / OUTPUT COMPONENTS OF CONTROL SYSTEM 19 18 Diagnostic connector 1 2 3 4 5 6 7 8 9 10 Engine ECU Air pressure / temperature sensor Engine speed sensor for top dead center Throttle valve position sensor Knock sensor Coolant temperature sensor Oxygen sensor (λ signal) Air condition request Ignition coil and spark plugs Instrument panel 11 12 13 14 15 16 17 18 19 Fuel injector Oxygen sensor (heater) Fuel pump Carbon canister solenoid valve Two step speed fan controller Compressor relay control Idli
WORKING MODULE TABLE FOR FUEL INJECTION / IGNITION SYSTEM Power supply relay Power supply (Power supply +12V) Fuel pump Power supply (15/54) A/C relay Idling speed step motor Malfunction indicator Fuel injector Ignition coil Carbon canister solenoid valve Engine ENGINE Coolant temperature sensor Throttle valve position sensor Line K Air pressure / temperature sensor Knock sensor · Cooling temperature overheat alarm light ·Decoder alarm light ·R.P.M.
WORKING PRINCIPLE This system is capable of controlling the actual tested air-fuel ratio under all engine speeds to stay close to the equivalent proportion of the chemical reaction, so as to protect the catalyst package and subsequently reduce the discharge of pollution. The oxygen sensor analyses the oxygen content of the discharge gas using real-time principle and makes it possible for the ECU to control the amount of injecting fuel to correct the air-fuel ratio. The fuel with a pressure of about 3.
ELECTRONIC CONTROL UNIT The ECU is located on the left of engine firewall. The ECU handles various signals from the sensors and controls the actuator so as to achieve the best possible operating condition. Many extra functions are added as compared with the previous model. While by the usage of a custom-made circuit board that can achieve many special functions, the integrated functions are enhanced so that the structure has considerably reduced in size and become much more compact.
- Engine coolant temperature - Air conditioning operation - Signal from oxygen sensor - Knock sensor for the accelerator meter on top of the engine crankshaft housing The air intake efficiency is obtained by calculating through the processing of absolute pressure, air intake temperature, engine speed, throttle valve position and other signals, and help to determine the air intake quantity of the cylinder.
WORKING PRINCIPLE OF ELECTRONIC FUEL INJECTION CONTROL AND ACTUATORS ※ Intake Pressure and Intake Air Temperature Sensor Purpose: detects manifold absolute pressure from 0.1~0.2bar and intake air temperature, provides engine with load information. Composition and principle: this sensor is composed of two different sensors (i.e. manifold absolute pressure sensor and intake temperature sensor), and is installed above pressurizer.
Troubleshooting: mainly check if there is short circuit or open circuit on the connection between 4 lines on sensor and ECU. If there is short circuit, open circuit or grounding between sensor wire harnesses.
Pins: 1 sensor signal ground (ECU17#) 2 5V power (ECU32#) 3 sensor signal (ECU16#) Troubleshooting: mainly check if there is short circuit or open circuit on the connection between 3 lines on sensor and ECU. Check to see if there is short circuit, open circuit or grounding between sensor wire harnesses. ※Coolant Temperature Sensor TF-W Purpose: this sensor is designed to provide coolant temperature information.
Hints: the vehicle is equipped with 2 water temperature sensors, one is single-pin water temperature sensor, providing the water temperature gauge with water temperature signal; the other is double-pin, providing the engine ECU with water temperature signal. Pins: this sensor has 3 pins, which can interchange for use. 1 coolant temperature sensor signal (ECU 39#) 2 sensor signal ground (ECU 35#) 3 another line connects water temperature signal of gauge.
value, failure mark restores. Installation hint: tightening torque is 20±5Nm. Pins: 1 Knock sensor signal 1 (ECU19#) 2 Knock sensor signal 2 (ECU20#) Troubleshooting: mainly check if there is short circuit or open circuit on the connection between 2 lines on sensor and corresponding ECU pins. If gasket is added during installation; if tightening torque is proper. If there is stitching defect between sensor and cylinder, or there is foreign matter between them.
Manifold absolute pressure signal is unreliable Engine coolant temperature signal is unreliable. Injector driver stage failure After oxygen sensor failure mark is set, fuel quantification closed-loop control is shut down, and the primitive fuel injection time stored in ECU is used to carry out fuel quantification.
Installation: to be fixed by the support of bracket under pilot trench of front windshield. Pay attention to waterproofing.
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Fuel injector 4 (the 2nd cylinder) Fuel injector 2 (the 3rd cylinder) Output of engine speed signal Sustained power supply Ignition switch The main relay Engine rotary sensor A Throttle position sensor Sensor ground 1 Oxygen sensor Knock sensor A Knock sensor B Fuel injector 3 (the 4th cylinder) Output Control of low speed fan Electronic ground 2 Output Ground Electronic ground 1 Ground A/C compressor switch Input Speed signal Input Power ground 1 Non-su
※Electrical fuel pump Function: Supply the fuel from the fuel tank to the engine at required pressure and flow (vary from individual system). Structure and working principle: The electrical fuel pump is comprised of direct current motor, vane pump and end cover (integrated with non-return valve, release valve and anti-electromagnetic interference elements). The pump and the motor are mounted on the same shaft and sealed in the same house.
Troubleshooting: The common malfunctions of the fuel pump are representation of insufficient fuel pressure, not pumping fuel and so on. It shall be verified firstly in troubleshooting that the fuel pressure is within rated range and the pipeline is leaked. In addition both the positive and negative pressure of the fuel tank will have impacts on the fuel system.
supply, short to ground or open, the malfunction flag bit is set. The closed loop control of the oxygen sensor and its memory precontrol are disabled, but the last data stored in its memory is valid. After the malfunction is fixed, the malfunction flag bit will be reset. Connected to the 87# pin of the main relay Working pressure: 350 kPa Resistance of the fuel injector: 11-16Ω Pins： Each fuel injector has two pins.
Structure and working principle: The step motor is a micro-motor, which is comprised of steel stators installed in a circle and a rotor. Each steel stator has a coil. The rotor is permanent magnet and the center of the magnet is a nut. All the coils of stators are always on. If the current direction of any coil is changed, the rotor will turn by an angle.
coil resistance. The ignition coil produces quite a lot heat under normal operation and the over temperature of ignition coil will result in such malfunctions as increase of the ignition coil’s resistance, unstable operation of the engine and engine stall. Ignition coil with double spark Primary winding: 0.
The ECU can indirectly control the purge airflow through controlling the charging time of the carbon canister solenoid valve based on the signals provided by various sensors of the engine. Fault diagnosis: The ECU doesn’t have the function of self-diagnosis for the carbon canister control valve, but has the function of self-diagnosis for the driving stage of control valve of carbon canister.
BASIC PRINCIPLE OF FAULT DIAGNOSIS FOR ELECTRONIC FUEL INJECTION SYSTEM ·RECORD OF MALFUNCTION INFORMATION The electronic control unit consistently monitors the operations of sensors, actuators, related circuits, malfunction alarm lights, voltage of battery and so on, even the operation of the electronic control unit itself, as well as carries out the examination on reliabilities of the signals output by the sensors, driving signals of actuators, and internal signals (such as oxygen closed loop control, kno
Illogical malfunction, there is signal but the signal is not logical. ·LIMP DRIVE If some detected important malfunctions last longer than the setting stabilizing time, ECU will take proper software measures, for example, disable some control functions including the oxygen sensor closed loop control and the like, replace some unreliable data with the setting values and etc.. Therefore even the working condition of the engine is quite bad at that time, but the car still can be driven.
The detailed procedures are: Turn on the ignition switch, but not start up the engine, ground the 7# pin of ECU by K wire for more than 2.5 seconds, then open the ground connection, after that the coding light starts flashing. After the K wire is grounded for more than 2.5 seconds the output of flashing code is the value of P-CODE.
DETAILED TABLE OF DIAGNOSTIC TROUBLE CODES Diagnostic trouble code: P0107 “Undervoltage in circuit of air intake pressure sensor” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Observe the “air intake pressure” in data flow and verify that it is maintained at 101kPa (the exact value is determined by the atmospheric pressure at that time).
Diagnostic trouble code: P0118“Over temperature indicated by engine coolant temperature sensor” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Observe the “coolant temperature” in data flow to verify that it matches to the engine temperature (the exact value is determined by the engine temperature at that time).
Diagnostic trouble code: P0122 “Undervoltage in circuit for throttle position sensor” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Observe the item of “throttle absolute opening” in the data flow to verify that the value is maintained within 4%-10% (the exact value varies from individual auto model.
Diagnostic trouble code: P0123 “Overvoltage in circuit for throttle position sensor” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Observe the item of “throttle absolute opening” in the data flow to verify that the value is maintained within 4%-10% (the exact value varies from individual auto model.
Diagnostic trouble code: P0130 “Malfunction in signal circuit of upstream oxygen sensor” (Note: The following diagnostic procedures are applicable only under the circumstances that the trouble code of P0135 does not appear simultaneously, in case that such trouble code appears at the same time, overhaul shall be carried out based on the following procedures after dealing with the malfunction of P0135 firstly.) Item No.
Diagnostic trouble code: P0132 “Overvoltage of circuit for upstream oxygen sensor” (Note: the following diagnostic procedures are applicable only under the circumstances that the trouble code of P0135 does not appear simultaneously, in case that such trouble code appears at the same time overhaul shall be carried out based on the following procedures after dealing with the malfunction of P0135 firstly.) Item No.
Diagnostic trouble code: P0134 “Signal malfunction of upstream oxygen sensor” (Note: The following diagnostic procedures are applicable only under the circumstances that the trouble code of P0135 does not appear simultaneously, in case that such trouble code appears at the same time, overhaul shall be carried out based on the following procedures after dealing with the malfunction of P0135 firstly.) Item No.
Diagnostic trouble code: P0135 “Malfunction in heating circuit of upstream oxygen sensor” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position.
Diagnostic trouble code: P0171 “Self adapting of closed loop control for air fuel ratio exceeding the upper limit” (Note: the following diagnostic procedures are applicable only under the circumstances that the trouble codes of intake air pressure sensor, carbon canister control valve, oxygen sensor and so on do not appear simultaneously, in case that such trouble codes appear at same time, overhaul shall be carried out based on the following procedures after dealing with other malfunctions firstly.
Diagnostic trouble code: P0172 “Self adapting of closed loop control for air fuel ratio exceeding the lower limit” (Note: The following diagnostic procedures are applicable only under the circumstances that the trouble codes of intake air pressure sensor, carbon canister control valve, oxygen sensor and so on do not appear simultaneously, in case that such trouble codes appear at same time, overhaul shall be carried out based on the following procedures after dealing with other malfunctions firstly.
Diagnostic trouble code: P0201 “Circuit malfunction of the 1 cylinder fuel injector” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of the 1 cylinder fuel injector on the wiring harness, and inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0202 “Circuit malfunction of the double cylinder fuel injector” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of the double cylinder fuel injector on the wiring harness, and inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0203 “Circuit malfunction of the triple cylinder fuel injector” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of the triple cylinder fuel injector on the wiring harness, and inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0204 “Circuit malfunction of the 4 cylinder fuel injector” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of the 4 cylinder fuel injector on the wiring harness, and inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0230 “Malfunction in control circuit of fuel pump” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Pull out the relay of fuel pump, turn the ignition switch to “ON” position, and verify that the voltage between the power supply terminal of fuel pump relay (i.e. 30# and 86# pin of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0325 “Malfunction in circuit of knock sensor” Item No. 1 2 3 4 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Disconnect the connector of knock sensor on the wiring harness, inspect with multimeter to verify that the resistance between 1# pin and 2# pin of this sensor is higher than 1MΩ.
Diagnostic trouble code: P0335 “Signal malfunction of crankshaft position sensor” Item No. 1 2 3 4 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Disconnect the connector of rotary sensor on the wiring harness, inspect with multimeter to verify that the resistance between 2# pin and 3# pin of this rotary sensor is about 770~950Ω under 20℃.
Diagnostic trouble code: P0336 “Malfunction of improper signal of crankshaft position sensor” Item No. 1 2 3 4 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Disconnect the connector of rotary sensor on the wiring harness, inspect with multimeter to verify that the resistance between 2# pin and 3# pin of this rotary sensor is about 770~950Ω under 20℃.
Diagnostic trouble code: P0340 “Malfunction of phase angle sensor signal” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of phase angle sensor on the wiring harness, inspect with multimeter to verify that the voltage between 1# pin and 3# pin of this phase angle sensor connector is about 12V.
Diagnostic trouble code: P0443 “Malfunction in control circuit of drive stage of carbon canister control valve” Item No. 1 2 3 4 5 6 Operation procedure Inspection results Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of carbon canister control valve on the wiring harness, inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0444 “Undervoltage in control circuit of drive stage of carbon canister control valve” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of carbon canister control valve on the wiring harness, inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0445 “Overvoltage in control circuit of drive stage of carbon canister control valve” Item No. 1 2 3 4 5 6 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of carbon canister control valve on the wiring harness, inspect with multimeter to verify that the voltage between 1# pin of this connector and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0480 “Malfunction in control circuit of relay of A/C condenser fan A” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Pull out the relay of A/C condenser fan, turn the ignition switch to “ON” position and verify that the voltage between the power supply terminal of the relay (i.e. 30# and 85# pins of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0481 “Malfunction in control circuit of relay of A/C condenser fan B” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Pull out the relay of A/C condenser fan, turn the ignition switch to “ON” position and verify that the voltage between the power supply terminal of the relay (i.e. 30# and 85# pins of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0500 “Malfunction of improper speed signal” Item No. Operation procedure 1 Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. 2 For the vehicles equipped with ABS system, verify that there is a diagnostic trouble code designed for ABS system. Inspection results Proceed to next step. Yes No Yes 3 4 5 Verify that the indicating needle of speedometer works properly. Verify that properly.
Diagnostic trouble code: P0506 “Idle speed lower than nominal idle speed” Item No. Operation procedure 1 Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. 2 Inspection results Verify that the adjusting screw of throttle, accelerator pedal stay and working condition of throttle are in good condition. Proceed to next step. Yes No Yes 3 4 Verify that the working condition of idle speed regulator is correct. A.
Diagnostic trouble code: P0507 “Idle speed higher than nominal idle speed” Item No. Operation procedure 1 Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. 2 Inspection results Verify that the adjusting screw of throttle, accelerator pedal stay and working condition of throttle are in good condition. Proceed to next step. Yes No Yes 3 4 Verify that the working condition of idle speed regulator is correct. A.
Diagnostic trouble code: P0508 “Undervoltage in control circuit of idle speed regulator” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of idle speed regulator and inspect with multimeter to verify that the resistances between pin A and D, pin B and C are 53±5.3Ω under 20℃.
Diagnostic trouble code: P0509 “Overvoltage in control circuit of idle speed regulator” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of idle speed regulator and inspect with multimeter to verify that the resistances between pin A and D, pin B and C are 53±5.3Ω under 20℃.
Diagnostic trouble code: P0511 “Malfunction in control circuit of idle speed regulator” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Disconnect the connector of idle speed regulator and inspect with multimeter to verify that the resistances between pin A and D, pin B and C are 53±5.3Ω under 20℃.
Diagnostic trouble code: P0560 “Improper voltage signal of system” Item No. Operation procedure 1 Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. 2 Inspect with multimeter to verify that the voltage of battery is about 12V. 3 4 5 Inspection results Verify that the resistances between the 44#, 45#, and 63# pins of ECU and 87# pin of the main relay are open or short to ground.
Diagnostic trouble code: P0562 “Undervoltage of system” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor, and turn the ignition switch to “OFF” position. Inspect with multimeter to verify that the voltage of battery is about 12V. Verify that the resistances between the 44#, 45#, and 63# pins of ECU and 87# pin of the main relay are excessive.
Diagnostic trouble code: P0563 “Overvoltage of system” Item No. Operation procedure 1 Connect the diagnostic tester and adaptor and turn the ignition switch to “OFF” position. 2 3 4 Inspection results Inspect with multimeter to verify that the voltage of battery is about 12V. Start up the engine, and verify that the charging voltage of generator is maintained within 9-16V under different speeds. Verify that the earth point of engine wiring harness is correct.
Diagnostic trouble code: P0601 “Malfunction of non-programmed check code in electronic control unit” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor and turn the ignition switch to “ON” position. Clear the diagnostic trouble code and reconfirm that this malfunction is a steady state malfunction. Replace ECU.
Diagnostic trouble code: P0645 “Malfunction in control circuit of A/C compressor relay” Item No. 1 2 3 Inspection results Operation procedure Connect the diagnostic tester and adaptor and turn the ignition switch to “OFF” position. Pull out the A/C compressor relay, turn the ignition switch to “ON” position and check if the voltage between the power supply terminal of relay (i.e. 30# and 85# pins of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0646 “Undervoltage in control circuit of A/C compressor relay” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor and turn the ignition switch to “OFF” position. Pull out the A/C compressor relay, turn the ignition switch to “ON” position and check if the voltage between the power supply terminal of relay (i.e. 30# and 85# pins of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P0647 “Overvoltage in control circuit of A/C compressor relay” Item No. 1 2 3 4 5 Inspection results Operation procedure Connect the diagnostic tester and adaptor and turn the ignition switch to “OFF” position. Pull out the A/C relay, turn the ignition switch to “ON” position and check if the voltage between the power supply terminal of relay (i.e. 30# and 85# pins of the relay) and the negative grid of power supply is about 12V.
Diagnostic trouble code: P1651 “Malfunction in control circuit of malfunction alarm light” Item No. 1 2 3 4 Inspection results Operation procedure Connect diagnostic tester and adaptor, and turn the ignition switch to “ON” position. Check the action of engine malfunction alarm light by using the “actuator action testing" function of diagnostic tester and observe whether the light is always on or off. Verify that the supply circuit of engine malfunction alarm light is open or short to ground.
PROCEDURES FOR FAULT DIAGNOSIS ACCORDING TO THE SYMPTOMS OF THE ENGINE A preliminary inspection should be carried out before implementing the steps of fault diagnosis according to the symptoms of engine: (1) Verify that there is no abnormal behavior with the ECU and malfunction indicator light (not applicable for car models without setting of malfunction indicator light). (2) Inspect with the diagnostic tester or flashing light to verify that there is no malfunction information record.
1) The engine is not running or running slowly during starting Item 1 2 3 4 Operation procedure Inspect with multimeter to see whether there is a voltage of about 10-12.5V between two battery terminals. Turn the ignition switch to “ON” position. Inspect with multimeter to see whether there is a voltage of about 10-12.5V between the terminals connecting the ignition switch and the positive grid of the battery.
2) The engine can run but cannot successfully start up during starting Item No. 1 2 3 4 5 Operation procedure Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Disconnect the cylinder distribution wire and connect it to the spark plugs, make a space of 5-10mm between the grid of the spark plug and engine body. Then turn on the engine with starting motor, verify that there is any bluish-white high-voltage spark.
12 13 14 15 16 17 18 19 20 21 22 Verify that the fuel is deteriorated or contaminated by water. Verify that the fuel pressure is lower than 350kPa. Close the fuel manometer valve. Connect the ignition switch again to re-operate the fuel pump in order to verify that the fuel pressure can be established. Yes No Yes No Yes Replace the fuel Proceed to Step 18. Proceed to next step. Proceed to Step 17. Proceed to next step. No Proceed to Step 16.
3) Difficult start-up of hot engine Item No. Operation procedure 1 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. 2 3 4 5 Inspection results Connect the fuel manometer valve. Short the 30# and 87# pins of the fuel pump relay to operate the fuel pump in order to verify that the fuel pressure is maintained at about 350kPa. Disconnect the connecting fuel pipe and turn off the ignition switch.
8 9 10 11 12 Replace the fuel and try the hot start again. Observe whether it can successfully start up. Verify that the fuel pipe has any blockage or bending and to see whether the pressure regulating valve functions of fuel pump is normally. Inspect with multimeter to see whether there is a voltage between two terminals of the plug in connector of fuel pump. Inspect with multimeter to see whether the resistance of fuel pump is correct. Verify that the fuel pump is jammed.
4) Difficult start-up under normal engine speed Item No. 1 2 3 4 5 6 7 8 9 10 11 12 Operation procedure Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Verify that the air filter is free of any blockage. After start up, verify that the air intake manifold pressure is maintained between 35-65 kPa at idle speed. Step on the throttle gently and observe whether it’s easy to start up.
No 13 14 15 16 17 18 19 Verify that the fuel return pipe has any leakage or bending. Disconnect the connector of idle speed actuator before the temperature of engine coolant reaches 350C in order to observe whether the engine speed is decreasing. Turn the ignition switch to “ON” position. verify that the voltages at following ECU pins are normal: 13# is at about 12V of battery voltage; 80# and 61# are at zero.
5) Difficult start-up of cold engine Item No. 1 2 3 4 5 6 7 8 Operation procedure Turn the ignition switch to “ON” position. Inspect with the diagnostic tester verify that there is any malfunction information record. Inspect with multimeter to see whether the coolant temperature sensor is normal. (Or connect a 1.5KΩ resistance in series with ECU’s pin of 39# and 35# to replace the function of the coolant temperature sensor to start up the engine.
9 10 11 12 13 14 15 16 17 18 19 (the connecting point will depend on the types of car models). Ground the 86# pin of the fuel pump relay directly. Connect the ignition switch to operate the fuel pump relay and the fuel pump in order to verify that the fuel pressure is maintained at about 350kPa. Provide a voltage supply of 12V with special connector between the battery and the fuel injector, and verify that the fuel injector functions normally.
6) Unstable idle speed at all time 1 2 3 4 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Verify that the EWD3 idle speed actuator or idle speed actuator with step motor is jammed. Connect the ignition switch and verify that the links between water temperature sensor, idle speed step motor and ECU are properly connected.
15 16 17 18 19 20 21 22 the ignition switch again to re-operate the fuel pump in order to verify that the fuel pressure can be established. Open the fuel manometer valve and clamp the fuel return pipe with the fuel tube clamp to stop the fuel return in order to verify that the fuel pressure can be established quickly. Verify that the fuel inlet pipe has any leakage or blockage. Verify that the fuel return pipe has any leakage or bending.
7) Unstable idle speed during engine warm-up 1 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. 2 Verify that the air filter is free of any blockage. 3 Run the engine at idle speed. Verify that the air intake manifold pressure is maintained between 35-65 kPa during warm-up. 4 5 6 7 Shut down the engine. Turn on the ignition switch and connect the adaptor between ECU and the wiring harness.
8) Unstable idle speed or stall with load (A/C and etc.) 1 2 3 4 5 6 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Turn on the A/C switch and connect the adaptor between ECU and the wiring harness. Measure and see whether the ECU’s A/C switch and pressure signal have any signal input. Verify that the pressure of A/C system, the magnetic clutch of compressor and A/C pump are normal.
9) Unstable idle speed after engine warm-up 1 2 3 4 5 6 7 8 9 10 11 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Turn the ignition switch to “ON” position and connect the adaptor between ECU and the wiring harness.
tube clamp to stop the fuel return in order to verify that the fuel pressure can be established quickly. 12 13 Verify that the fuel inlet pipe has any leakage or blockage. Verify that the fuel return pipe has any leakage or bending. No Yes No Yes No Yes 14 Run the engine at idle speed until the coolant temperature reaches its normal value in order to verify that the ignition advance angle is normal. 15 Disconnect the coolant temperature sensor to verify that the engine is normal.
10) A/C system malfunction 1 2 3 4 5 Verify that there is enough refrigerant and the A/C belt, A/C clutch and pressure switch are in good condition. Run the engine at idle speed and turn on the A/C switch. Inspect with the diagnostic tester to see whether there is any malfunction with the A/C thermo-sensitive resistance. Turn on the A/C switch and connect the adaptor between ECU and the wiring harness. Measure and see whether the ECU’s A/C switch and A/C pressure have any signal input.
11) Periodically instability (the memory has to be restored after ECU’s power-off) 1 2 3 4 5 6 7 8 9 10 11 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Verify that the air filter is free of any blockage. Verify that the air intake pressure is maintained between 35-65 kPa at idle speed.
12 voltage cable have any damaged parts or cracks. No Proceed to next step. Verify that the spark plug is normal. Yes No Replace the ECU. Replace the spark plug. E-80 PDF created with pdfFactory Pro trial version www.pdffactory.
12) Too high idle speed (the memory has to be restored after ECU’s power-off) 1 2 3 4 5 6 7 8 9 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Verify that the fastener connected to the accelerator pedal is jammed or too tight.
13) Malfunction to increase the speed or stall during acceleration 1 2 3 4 5 6 7 8 9 10 11 12 Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record. Verify that the air filter is free of any blockage. Run the engine at idle speed in order to verify that the idle speed is normal. Verify that the air intake pressure is maintained between 35-65 kPa at idle speed.
13 14 15 16 Verify that the fuel inlet pipe has any leakage or blockage. Verify that the fuel return pipe has any leakage or bending. Turn the ignition switch to “ON” position and connect the adaptor between ECU and the wiring harness. Verify that the voltages at following pins of ECU including signal output terminal and grounding terminal of the throttle position sensor, and pins of 32# and 33# (used as sensor’s power supply of 4.5-5V) are normal.
14) Slow respond during acceleration 1 Turn the ignition switch to “ON” position. Verify with diagnostic tester to see whether there is any malfunction information record. 2 Shut down the engine and verify that the air filter is free of any blockage. 3 Run the engine at idle speed in order to verify that the idle speed is normal. 4 5 6 7 8 9 10 11 Verify that the air inlet pipe pressure is being maintained between 35-65 kPa at idle speed.
12 13 14 15 16 Turn off the fuel manometer valve. Connect the ignition switch again to re-operate the fuel pump in order to verify that the fuel pressure can be established. Turn on the fuel manometer valve and clamp the fuel return pipe with the fuel tube clamp to stop the fuel return in order to verify that the fuel pressure can be established quickly. Yes Proceed to next step. No Proceed to Step 14 Verify that the fuel inlet pipe has any leakage or blockage.
15) Poor and weak performance during acceleration 1 2 3 4 5 6 7 8 Verify that there are any malfunctions such as slipping of clutch, low pressure of tires, delay in braking, and wrong size of tires or inaccurate four-wheel alignment. Verify that the throttle can be fully opened. Turn the ignition switch to “ON” position. Inspect with the diagnostic tester to see whether there is any malfunction information record.
11 12 13 14 15 16 17 18 contaminated with water. Verify that the fuel pressure is lower than 350kPa. Turn off the fuel manometer valve. Connect the ignition switch again to re-operate the fuel pump in order to verify that the fuel pressure can be established. Turn on the fuel manometer valve and clamp the fuel return pipe with the fuel tube clamp to stop the fuel return in order to verify and see whether the fuel pressure can be established quickly.
SAFETY PRECAUTIONS OF SYSTEM MAINTENANCE SAFETY PRECAUTIONS IN DIAGNISIS AND MAINTENANCE OF THE GASOLINE INJECTION ELECTRONIC CONTROL SYSTEM (1) Removal/installation requirements of controller The battery negative grid must be disconnected first, followed by the removal of controller prior to carrying out electric welding or baking finish; In removing/installing the controller, the ignition switch must be turned to “OFF” position to avoid being damaged; The power supply wire should not be removed from the b
The spare parts should be taken out from its packing only before the assembly. Any part without proper packing is not allowed to be used; Pay attention not to damage the O ring while assembling the fuel injector. A small amount of lubricating oil should be applied on the O ring for assembly convenient. After the system has been opened up, as far as possible not to use compression air and move the car around.
