Service Manual for Chery QQ6 (UMC EFI for 473F Engine) After Sales Service Department of Chery Automobile Sales Co., Ltd.
CONTENTS CHAPTER ONE DISASSEMBLY AND INSTALLATION OF ELECTRONIC FUEL INJECTION SYSTEM.......................................................................................................................4 I. Disassembly and Installation of Components of Electronic Fuel Injection System ..................4 CHAPTER TWO PRINCIPLE OF ELECTRONIC FUEL INJECTION SYSTEM ...................6 I. Overhaul of System Components ............................................................................................
11.4 Front Oxygen Sensor Failure ......................................................................................38 11.5 Rear Oxygen Sensor Failure .......................................................................................40 11.6. Coolant Temperature Sensor Failure .........................................................................42 11.7 Failure in Driver Stage of Injector ..............................................................................43 11.
Chapter One Disassembly and Installation of Electronic Fuel Injection System I. Disassembly and Installation of Components of Electronic Fuel Injection System 1. Disassembly and installation of engine control unit (ECU). 2. Position and disassembly of intake air pressure sensor. 3. Position and disassembly of camshaft position sensor. 4. Remove fixing hoop of intake hose.
. Remove the four fixing bolts of electronic throttle body. Pull out the connector and take out the electronic throttle body. 6. Use a screwdriver to press down the fixed clip of the injection nozzle connector and then pull out the connector. 7. Use a screwdriver to press down the fixed clip of the knock sensor connector and then pull out the connector. 8. The water temperature sensor is behind the thermostat seat. 9. Pull out the connector of the ignition primary coil by hand. 10.
Chapter Two Principle of Electronic Fuel Injection System I. Overhaul of System Components 1. Intake Air Temperature Pressure Sensor 1.1 Function of the sensor: Detect air intake pressure and temperature in air intake manifold, which will be provided to ECU as main load signal of engine; ECU will calculate injection pulse-width based on this signal. 1.
1.3 Parameters of technical features This sensor is designed to be mounted on the plane of auto engine intake manifold. The pressure connecting pipe together with the temperature sensor protrudes inside the intake manifold and an O gasket is used to enable atmosphere-proof. If it is mounted on an auto through an appropriate method (picks up pressure from the intake manifold and the pressure connecting pipe tilts down etc.
2. Tachogenerator of Engine 2.1 Function of the sensor: As one of the uppermost sensors of engine, the tachogenerator of engine provides ECU with rev signal, acceleration signal and crank angle signal etc. of engine. ECU will calculate injection pulse-width, injection time and ignition timing through these signals and provide the instruments with rev signal of engine. 2.
2.3 Parameters of technical features Item Resistance under a room temperature of 20°C Inductance Output voltage at a crankshaft revolution of 416rpm Min. 774 310 >1650 Unit Value Typical 860 Max. 946 370 430 Ω mH mV 2.4 Installation attentions: l For the inductive tachogenerator, it is permitted to take out from its pack before it is assembled to the auto or testing device right away. l Inductive tachogenerator is assembled by press in method but not hammer tapping.
3. Phase Sensor 3.1 Function of the sensor: Provide ECU with phase signal, i.e. help crankshaft position sensor of engine to judge it is then at compressing top dead center or air exhaust top dead center. 3.2 Principle of the sensor: The phase sensor is consisted of the Hall generator installed on the valve cover and the signal wheel machined on the intake camshaft.
Coolant temperature sensor 4.3 Parameters of technical features (1) Data limit Item Rated voltage Rated resistance at 20℃ Range of running temperature Max. measuring current passing the sensor Permissible vibration acceleration Value Can only be run by ECU 2.5±5% -30 to +130 1 Unit 600 m/s2 kΩ ℃ mA 4.4 Installation attentions Coolant temperature sensor is installed on the cylinder body and the copper heat conducted socket is inserted into coolant.
5. Knock Sensor 5.1 Function of the sensor: The knock sensor provides ECU with knock signal. When the engine generates knock, ECU will control to gradually reduce ignition advance angle to eliminate the knock; when no knock occurs during certain strokes, ECU will gradually increase ignition advance angle to enable the engine to obtain max. torque. 5.2 Principle of the sensor: Knock sensor is a kind of vibrating acceleration sensor and is assembled on cylinder block.
The electronic throttle body can automatically open or close the throttle according to the driver’s will to apply the accelerator pedal to let the engine work under the corresponding operating mode. The electronic throttle has cancelled the conventional throttle guy and the opening of throttle is controlled by ECU based on the signal from accelerator pedal and other signals (such as A/C, power assisted steering, back and gearshift etc.) through an electronic step motor inside the electronic throttle body.
signals fed back by the oxygen sensor, i.e. control injection pulse-width to let the mixed gas always maintain an approximately ideal air-fuel ratio (14.7:1). 7.2 Principle of the sensor: Sensing element of oxygen sensor is a kind of ceramic tube with holes, and outside of tube walls are surrounded by engine exhaust gas and inside is air. Ceramic sensor element is a kind of solid state electrolyte with electrical heating tube inside (as shown in the figure).
(close to 100mV). The signal voltage will mutate near theoretical equivalent air-fuel ratio (λ=1), see the figure above. Main relay 者 87# Oxygen sensor Every oxygen sensor bears a cable and the other end of the cable is the wire connector. The wire connector of oxygen sensor produced by our company has four pins: No.1 connects to the positive pole of heater power supply (white); No.2 connects to the negative pole of heater power supply (white); No.3 connects to signal negative pole (gray); No.
8. Fuel Pump Assembly 8.1 Function of fuel pump: Fuel pump is used to deliver the fuel in the fuel tank to inside the engine at a certain pressure for combustion. It also needs to regulate the fuel pressure duly as required by system pressure (non fuel return type). Generally, the system fuel pressure provided by fuel pump is around 3.5-4bar. 8.
wrapping material with care only when installing. The viser can be taken off only when the fuel pump is to be installed. Takeoff of the filter net at fuel inlet is absolutely not allowed. The foreign material that enters the fuel inlet of the fuel pump or the filter net may lead to damage of the fuel pump. 8.5 Failure effects and judgment method l Failure effect: strong running noise, poor acceleration, failure to start (starting difficulties) etc.
1. O-ring 2. Filter net 3. Injector body with electric connector 4. Coil 5. Spring 6. Valve needle with coil armature 7. Valve seat with nozzle plate Cross-section view of electromagnetic injector Connects to 87# pin of the main relay 1# cylinder 1# cylinder 1# cylinder 1# cylinder Injector Circuit diagram of electromagnetic injector 9.3 Parameters of technical features Item Min. Operating pressure (pressure difference) Injector electric resistance at 20℃ 11 Value Typical 350 Unit Max.
l surface of the O-ring at the upside of the injector where it connects with the fuel distributing pipe. Be careful not to let engine oil contaminate inside of the injector and the nozzle. Place the injector in its bracket vertically along injector bracket, then fix it to the bracket with retaining clips. Note: ① By location mode, the remaining clips for injector fall into axial location remaining clip and axial and radial location remaining clip; misuse should be avoided.
casing. When one of the primary windings grounding channel is connected, the primary winding is in charging. Once the primary winding circuit is cut off by ECU, the charging will be stopped. At the same time, the high voltage is sensed in the secondary winding and making the spark plug discharging. There is a different with the distributor ignition coil: for the ignition coil ZS - K2×2, there is one spark plug on both side of the secondary winding, so the both spark plugs can ignite at the same time.
11. Spark Plug The operating conditions of spark plug is extremely inclement, it is exposed to high pressure, high temperature and impact as well as strong corrosion from combustion product; therefore, it is a wearing part. 11.1 Outline drawing Covered with rivet Mono-pole Covered with rivet Triple-pole 11.2 Thermal performance The spark plug must maintain a proper temperature to keep good working order.
scratch is present on the cylinder wall. Pearl overheating check if the spark plug type matches, and then replace with the spark plug with lower heat value (rapid heat radiation). 11.6 Regular replacement and use overdue The spark plug is the low-value consumption goods. Though cheaper compared with other matching parts, its ignition performance directly affects the performance of the engine. Therefore, it needs regular replacement.
pressure difference between the inlet and the outlet of the canister control valve. The canister control valve will be closed when there is not any electric pulse. 87# pin of main relay Canister control valve ΔP is the difference between environmental pressure Pu and intake manifold pressure Ps Cross-section view of canister control valve 1 From fuel tank 2 Canister 3 Atmosphere 4 Canister control valve 5 To intake manifold 6 Throttle Installation drawing of canister control valve 12.
l Simple measurement method: With the joint removed, turn the digital multimeter to Ohm shift, and then connect the two meter pens respectively to both pins of the canister control valve. The rated resistance at 20℃ should read 26±4Ω. 13. Electronic Accelerator Pedal 13.
gases as carbon dioxide and water etc. At 300-800℃, the conversion efficiency of three-way catalytic converter is maximum; with a temperature below this scope, the conversion efficiency will be very poor, while, with a temperature above this scope, the three-way catalytic converter may be burnt out. Three-way catalytic converter can exert better conversion efficiency only when the oxygen sensor works.
1. High speed fan control (corresponds to ECU50#); 2. Low speed fan control (corresponds to ECU68#); The operating mode of fan after engine stops: 1. Failure of intake air temperature sensor of engine, delay 60s; 2. Failure of intake air temperature sensor of engine, delay 60s; 3. Engine coolant temperature exceeds 100.5℃, delay 60s; 4. Engine coolant temperature exceeds 70.5℃, delay 60s. 16. Position Sensor of Double Brake Pedal 16.1 Function: 制动开关传感器是将刹车信号送给 ECU，ECU 根据（原文不全） 16.
Clutch position switch provides ECU with the signal of clutch position, but this signal can only be used to distinguish between disengaging and engaging positions of the clutch. 17.2 Working principle: ECU provides clutch position switch with a 12V power supply; when the clutch is under disengaging state, the power supply will ground and ECU will lose 12V high potential signal, by which the position of the clutch can be judged. Clutch position switch 离 合 器 位 置 开 关 18.
Chapter Two Fundamental Principle for Failure Diagnosis of Electronic Fuel Injection System 1. Failure Information Records The ECU monitors sensor, actuator, related circuit, malfunction indicator and battery voltage etc., and even EUC itself continuously. At the same time, the ECU inspect the reliability test on sensor signal output, actuator driving signal and internal signal (e.g.: closed loop control, knock control, idle speed control and accumulator voltage control etc.).
information record will be stored in memory after the identified failure disappears (after troubleshooting). When a failure is identified for the first time, Hz will be set as its initial value 40. If failure status does not change, then this numerical value will maintain all along.
Figure 3-1 ISO 9141-2 Standard Diagnostic Connector 8. Clearing Failure Information Records After the failure is removed, the failure information records in memory should be cleared. The diagnostic trouble code can be cleared through the following approaches: When the numerical value of frequency counter in ECU reaches zero, the failure information records in failure memory will be automatically cleared.
4 P0032 Too high voltage in heating control circuit of upstream oxygen sensor class31 5 P0105 Signal failure of intake air pressure sensor class31 6 P0106 Improper signal from intake air pressure sensor class31 7 P0107 Too low voltage in signal circuit of intake air pressure sensor class31 8 P0108 Too high voltage in signal circuit of intake air pressure sensor class31 9 P0112 Too low voltage in signal circuit of intake air temperature sensor class5 10 P0113 Too high voltage in sig
41 P0340 Failure in signal circuit of phase sensor class5 42 P0341 Improper signal from phase sensor class5 43 P0342 Too low voltage in signal circuit of phase sensor class5 44 P0343 Too high voltage in signal circuit of phase sensor class5 45 P0444 Failure in control circuit of canister control valve class31 46 P0458 Too low voltage in control circuit of canister control valve class31 47 P0459 Too high voltage in control circuit of canister control valve class31 48 P0480 Failu
Too high voltage in relay control circuit of electronic cooling fan (high 77 P0694 speed) class5 78 P0704 Improper clutch pedal signal class5 79 P1336 Restrictive effect of safety monitoring torque of electronic throttle class34 The deviation between physical location and target location of electronic 80 P1545 throttle overruns class34 81 P1558 Too large opening resistance of electronic throttle class34 82 P1559 Failure in self-study process of electronic throttle class34 System volt
Self-study value of closed loop air fuel ratio control is above the upper limit 106 P2191 (heavy load zone) class5 Self-study value of closed loop air fuel ratio control is below the lower limit 107 P2192 (heavy load zone) class5 Main power cord Engine theft-proof module 1 Electrical Schematic Diagram of Diagnostic Interface
11. The Steps for Implementation of Failure Diagnosis According to Failure Information Records 11.1 Electronic Throttle Failure Failure codes: P012, P0122, P0123, P022, P0222, P0223, P1336, P154, P1558, P1559, P1564, P1565, P1568, P1579, P1604 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”.
11.2 Knock Sensor failure Failure codes: P0324, P0327, P0328 No. Operating steps Result Follow up steps 1 Close the ignition switch, and the engine stops. 2 Pull out the joint of knock sensor on harness, use a multimeter to check if both resistance values between 1# and 2# pins and between 1# pin and shielded wire (sensor shield) pin of knock sensor are more than 1MΩ.
11.3 Air Pressure Sensor Failure Failure codes: P0102, P0103, P0112, P0113 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull out joint of intake air pressure sensor on harness; use a multimeter to check if a 5V voltage is present between 2# and 3# pins of the joint. Yes 4 No Next step Between ECU and harness, use a multimeter to respectively check if it is break or short circuit between 42# and 33# pins of ECU and 1#, 2#, 3#, 4# pins of sensor joint.
11.4 Front Oxygen Sensor Failure Failure codes: P0130, P0131, P0132, P0134, P0135 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull off the connector of harness of oxygen sensor. Check the voltage between pin 1# (+) and 2# (-) with multimeter and detect if it is around 12V. Yes Next step No 4 Use a multimeter to check if the resistance value between 1# and 2# pins of the oxygen sensor is between 2Ω and 5Ω at 23℃.
12 Connect special diagnostic tester for Chery to read part of data stream of the engine, and then carefully observe part of data stream of the sensor; apply the accelerator pedal to bottom and then rapidly release it, observe if the output voltage of the oxygen sensor can reach below 100mv.
11.5 Rear Oxygen Sensor Failure Failure codes: P0136, 0137, 0138, 0036, 0037, 0038, 0054 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull off the oxygen sensor connector of harness. Check the voltage between pin 1# (+) and 2# (-) with multimeter and detect if it is around 12V. Yes Next step No 4 Use a multimeter to check if the resistance value between 1# and 2# pins of the oxygen sensor is between 2Ω and 5Ω at 23℃.
part of data stream of the engine, and then observe if part of data stream of the oxygen sensor is around 100 under standard idling operation. 12 Start the engine and let it run at idle speed until coolant temperature reaches normal value.
11.6. Coolant Temperature Sensor Failure Failure codes: P0112, P0113 No. Follow up steps Put the ignition switch to “ON”. 2 Pull out joint of coolant temperature sensor on harness; use a multimeter to check if the magnitude of voltage between 1# (+) and 2# (-) pins of this joint is around 5V. Yes Next step No 4 Use a multimeter to check if the resistance value between 1# and 2# pins of the sensor is in proportion to its temperature (refer to relevant part in this service manual).
11.7 Failure in Driver Stage of Injector Failure codes: P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271 No. Operating steps Result Follow up steps 1 Close the ignition switch, and the engine stops. Next step 2 Pull out each electromagnetic injector joint on harness in turn, and then lap the two pins of multimeter between 2# pin of the joint and the engine. Next step 3 Put the ignition switch to “ON”.
11.8 Failure in Driver Stage of Canister Control Valve Failure codes: P0443, 0444, 0445 No. Operating steps 1 Start the engine and let it run at idle speed until engine coolant temperature reaches normal value. 2 Pull out canister control valve joint on harness; use a multimeter to check if an around 8.6V battery voltage is present between two pins of this joint.
11.9 Failure in Driver Stage of Malfunction Indicator Lamp (MIL) Failure codes: P1677, P1678, P1679 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON” 2 Disassemble the dashboard, and then use a multimeter to check if it is break or short circuit between 29#, 30# pins at instrument end and 62#, 81# pins of ECU.
11.10 Failure in Driver Stage of 1#, 2# Coils of Step Motor Failure codes: P1682, 1683 No. Operating steps 1 Turn on the ignition switch but do not start the engine. 2 Pull out connector of the electronic throttle, and then check if the resistance value between 5# and 3# pins of the connector is around 6.1Ω. Yes Pull out the connector, and then use a multimeter to check if a 12V alternate voltage is present between 5# and 3# connectors of the electronic throttle.
11.11 Crankshaft Position Sensor Failure Failure code: P0016 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull out camshaft position sensor joint on harness, and then use a multimeter to check if the voltage between 1# pin of this joint and ground wire is around 12V (battery voltage).
11.12 Craftshaft Position Sensor Failure Failure codes: P0321, P0322, P0219 No. 1 2 3 4 5 Operating steps Result Put the ignition switch to “ON”. Follow up steps Next step Pull out crankshaft position sensor joint on harness, use a multimeter to check if it is short or break circuit between 1# pin of this joint and 34# pin of ECU.
11.12 Ignition Coil Failure No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull out ignition coil joint on harness, and then use a multimeter to check if the voltage between 3# pin of this joint and ground wire is an around 12V battery voltage. Yes Next step No Check the circuit Pull out ignition coil joint on harness, and then use a multimeter to check if it is short or break circuit between 1# pin of this joint and 5# pin of ECU.
11.13 Accelerator Pedal Position Sensor Failure Failure codes: P2106, P2122, P2123, P2127, P2128, P2138 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull out accelerator pedal position sensor joint on harness, and then use a multimeter to check if an around 5V voltage signal is present between 3#, 6# pins of this joint and ground wire.
11.14 Double Brake Switch Failure codes: P0571, P0504 No. Operating steps Result Follow up steps 1 Put the ignition switch to “ON”. 2 Pull out brake switch joint on harness, and then use a multimeter to check if it is short or break circuit between 1#, 2# pins of this joint and 21#, 58# pins of ECU. Yes Next step No Check the circuit Close the ignition switch, and then check if an around 12V battery voltage is present on 3# pin of the switch joint.
11.15 Theft-proof Control System Failure No. Operating steps Result Follow up steps 1 Insert the ignition key into the ignition lock. 2 Put the ignition switch to ON position, and then observe if engine failure indicator lamp or EPC lamp works normally (quick flash of failure indicator lamp or EPC lamp indicates a abnormal condition).
12. Steps for Implementation of Failure Diagnosis by Engine Symptom 12.1 Perform Preliminary Inspection First before Following the Steps for Implementation of Failure Diagnosis by Engine Symptom. (1) Make sure that ECU and failure indicator lamp (or EPC lamp) have no off-normal phenomenon (excluding the models that have no failure indicator lamp). (2) Use a failure diagnostic tester to check and make sure no failure information record exists.
Check that grounding of wire harness is clean and firm. Check that vacuum pipeline is unbroken, twisted and in right connection. Check that there is no obstruction in pipe. Check that air intake pipe is not squashed or damaged. Check that the seal between throttle body and intake manifold is perfect. Check that ignition cable of ignition system is unbroken, no ageing and in right wiring. Check that wires are in right connection, no loosing or poor connection for connectors.
12.2 The Engine Does not Rotate or Rotates Slowly when Starting No. 1 2 3 4 5 6 7 Operating steps Result Follow up steps Use a multimeter to check if a voltage around 10-12.5V is present between two battery terminals. Yes Next step No Repair replace battery Put the ignition switch to “ON”. Use a multimeter to check if a battery voltage around 10-12.5V is present on the terminal on the ignition switch that connects with anode of battery.
12.3 When Starting, Engine Can be Dragged to Rotate but Can not Start with Success. No. 1 2 3 4 5 6 7 8 9 10 11 Operating steps Result Follow up steps Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists.
12 13 14 15 16 17 18 19 20 21 22 work correctly. No Replace the fuel injector Check if fuel is bad or moisture. Yes Replace fuel No 18 Check if the fuel pressure value is below 400 kPa. Yes Next step No 17 Close the fuel manometer valve. Re-engage the ignition switch to let the fuel pump run for a period of time, and then check if fuel pressure can be built up.
12.4 Warm Starting Difficulty No. 1 2 3 4 5 6 7 8 9 10 11 Operating steps Result Follow up steps Put the ignition switch to “ON”. Use a special diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Connect fuel manometer valve. Short 30# and 87# pins of fuel pump relay to make the fuel pump run, and then check if fuel pressure is around 400kPa.
12 Check if the fuel pump is stopped up. Yes Replace fuel pump No Replace ECU Note: Warm starting difficulty is in connection with many systems, such as battery, throttle body and water temperature sensor etc. as well as mechanical part of the engine, such as valve sealing. Thermal expansion of engine under warm state may lead to rise of engine resistance.
12.5 Engine Speed is Normal, but it is Difficult to Start at any Time No. Operating steps Result Follow up steps Put the ignition switch to “ON”. Use a special diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check the air cleaner and look if it is open.
14 15 16 17 18 19 No Replace fuel pressure regulator When engine coolant is at low temperature, pull out electronic throttle body on harness and observe if engine revolution will rise. Yes Next step No Check electronic throttle body for damage Put the ignition switch to “ON”. Check if voltage on the following pins of ECU is normal: if it is a battery voltage around 12V on 12#, 14#, 15# pins; if the voltage between 51#, 53#, 3#, 61#, 80# pins and the wire is zero.
12.6 Cold Starting Difficulty No. 1 2 3 4 5 6 7 8 9 10 11 Operating steps Result Follow up steps Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Use a multimeter to check if the coolant temperature sensor is normal. (A 2.8KΩ electric resistance can also be connected in series between 39# and 17# pins of ECU to start the engine in stead of the coolant temperature sensor.
12 13 14 15 16 17 18 19 No 17 Yes Next step No 16 Close the fuel manometer valve. Re-engage the ignition switch to let the fuel pump run for a period of time, and then check if fuel pressure can be built up. Yes Next step No 15 Open the valve of fuel gauge and clamp the oil return pipe by oil return baffle so that the oil can not return. Check if the oil pressure occurs immediately.
12.7 Unsteady Idle Speed at Any Time 1 2 3 4 5 6 7 8 9 10 11 12 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check if electronic throttle system of engine works normally.
13 14 15 16 17 18 19 Check if the fuel pressure value is below 300kPa. Yes Next step No 17 Close the fuel manometer valve. Re-engage the ignition switch to let the fuel pump run for a period of time, and then check if fuel pressure can be built up. Yes Next step No 16 Open the valve of fuel gauge and clamp the oil return pipe by oil return baffle so that the oil can not return. Check if the oil pressure occurs immediately.
12.8 Unsteady Idle Speed during Warming up Process 1 2 3 4 5 6 7 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check the air cleaner and look if it is open. Yes Next step No Replace After starting successfully, check if air intake consumption of the engine at idle speed is around 300Kg/h (remember to check if cylinder pressure is normal).
12.9. Unsteady Idle Speed after Warming up 1 2 3 4 5 6 7 8 9 10 11 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists.
12 13 14 15 16 17 18 19 Check if there is leaking or jam in oil intake pipe. Check if the oil return pipe is bended or jammed. Let engine run at idle speed, after coolant temperature reaches normal value, then use a diagnostic tester to check if ignition advance angle is normal.
12.10 Unsteady Idle Speed or Extinguish with Load (A/C etc.) 1 2 3 4 5 6 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Turn on A/C switch, connect an adaptor Yes between ECU and harness, and then measure No 75# pin of ECU to see if input signal is present (high potential signal loaded by A/C switch through high and low voltage switches).
12.11 Periodic Unsteadiness (Have to Perform Self-study again after ECU is Power off) 1 2 3 4 5 6 7 8 9 10 11 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check the air cleaner and look if it is open.
12 Check if the spark plug is in right conditions. Yes Replace ECU No Replace spark plug Note: For periodic unsteadiness, mainly check air intake system for air leak or electronic throttle body for failure. Following are the steps for inspection of electronic throttle body: while turning on ignition key, throttle may jiggle; during self-checking procedure, throttle should act with actions of accelerator pedal.
12.12 Too High Idle Speed (Have to Perform Self-study again after ECU is Power off) 1 2 3 4 5 6 7 8 9 10 11 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check if throttle valve plate is locked and if failure exists in electronic throttle body.
12.13. Engine Revolution Speed is too Low or Flameout 1 2 3 4 5 6 7 8 9 10 11 12 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Check the air cleaner and look if it is open.
13 14 15 16 not return. Check if the oil pressure occurs immediately. No Repair and replace fuel injector and oil pipe Check if there is leaking or jam in oil intake pipe. Yes Repair or replace oil intake pipe No Replace oil pump Yes Repair or replace oil return pipe No Replace fuel pressure regulator Put the ignition switch to “ON”.
12.14 Slow Response when Accelerating 1 2 3 4 5 6 7 8 9 10 11 12 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step Turn off the engine. Check the air cleaner and look if it is open. Yes Next step No Replace Run the engine at idle speed and check if the engine revolution speed is normal at idle speed.
13 14 15 16 Open the valve of fuel gauge and clamp the oil return pipe by oil return baffle so that the oil can not return. Check if the oil pressure occurs immediately. Yes Replace the pressure regulator No Repair and replace fuel injector and oil pipe Check if there is leaking or jam in oil intake pipe. Yes Repair or replace oil intake pipe No Replace oil pump Yes Repair or replace oil return pipe No Replace the pressure regulator Check if the oil return pipe is bended or jammed.
12.15 Poor Performance and Disability when Accelerating. 1 2 3 4 5 6 7 8 9 10 11 Check if failure occurs, such as clutch slipping, low tire pressure, brake delay, wrong tire size and incorrect four-wheel alignment. Yes Repair No Next step Check if the electronic throttle can be full opening. Yes Next step No Repair or replace the throttle Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists.
12 13 14 15 16 17 18 Close the fuel manometer valve. Re-engage the ignition switch to let the fuel pump run for a period of time, and then check if fuel pressure can be built up. Yes Next step No 14 Open the valve of fuel gauge and clamp the oil return pipe by oil return baffle so that the oil can not return. Check if the oil pressure occurs immediately. Yes Replace the pressure regulator No Repair and replace fuel injector and oil pipe Check if there is leaking or jam in oil intake pipe.
12.16 Unable to Reach the Maximum Revolution when Accelerating 1 2 3 4 5 6 7 8 9 10 11 12 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step With engine off, check if air cleaner is smooth (can not simply rely on visualization, remove the air cleaner and then perform test drive again) and if air intake system is chocked.
catalytic converter are jammed. No Replace ECU Note: In case the engine is unable to reach its maximum revolution when accelerating, mainly check if exhaust pipe is chocked and air cleaner is smudgy. In addition, for electric control system of A21, in case of a failure in crankshaft or camshaft position sensor, ECU will take restrictive driving measures to restrict engine revolution to exceed certain value, which should be noted during maintenance process.
12.17 When Releasing Accelerator Pedal after Acceleration, Unsteady Idle Speed Occurs at Instant, even Extinguishes. 1 2 3 4 5 6 7 8 9 10 11 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. Yes Remove the failure displayed No Next step With engine off, check if air cleaner is smooth (can not simply rely on visualization, remove the air cleaner and then perform test drive again) and if air intake system is chocked.
kPa. 12 No Check if the exhaust system and three-way Yes catalytic converter are jammed. No 15 Replace or clean Replace ECU Note: For an electric control motor with the electronic throttle body, the main actuators of its air intake system are air flow meter and electronic throttle body.
12.18 A/C System Failure 1 2 3 4 5 Check if there is enough coolant, if the A/C belt, Yes the A/C clutch and the pressure switch are in No good condition. Next step Let engine run at idle speed and turn on A/C switch. Enter A/C self diagnosis mode to check the A/C system for failure. Yes Remove the failure displayed No Next step Turn on the A/C switch and connect an adaptor between ECU and harness. Measure 75# pin (A/C switch) of ECU and see if there are input signals on it.
13. Safety Precautions for System Maintenance 13.1 Safety Precautions for Diagnosis and Maintenance of Gasoline Injection Electronic Control System (1) Disassembly and assembly requirements for electronic control unit (ECU): Controllers shall be removed before welding or paint-baking; When disassembling and installing the controller, be sure to set ignition switch to CLOSE position and disconnect the battery with the system for fear to damage the engine control unit during disassembly and installation.
If disassembled parts can not be repaired or for other processing immediately, store them properly. The spare parts can be taken out of their package only when they are to be installed; do not use the spare parts without package or with package heavily damaged; When installing an injector, be careful not to damage the O-gaskets at both ends of the injector; for installation convenience, apply a little lubricant on the O-gaskets.
