Engine Electrical System

7) Unstable idle speed during engine warm-up
Yes
Fix the indicated
malfunction
1
Turn the ignition switch to “ON” position.
Inspect with the diagnostic tester to see
whether there is any malfunction information
record.
No Proceed to next step.
Yes Proceed to next step.
2 Verify that the air filter is free of any blockage.
No Replace
Yes Proceed to next step.
3
Run the engine at idle speed. Verify that the air
intake manifold pressure is maintained
between 35-65 kPa during warm-up.
No
Fix the leakage of air
intake system
Yes Proceed to next step.
4
Shut down the engine. Turn on the ignition
switch and connect the adaptor between ECU
and the wiring harness. Verify that the voltages
at air intake temperature sensor, water
temperature sensor, and ECU’s pins of 32# and
33# (used as sensor power supply of 4.5-5V)
are normal.
No Service
Yes Proceed to next step.
5
Disconnect the connector of idle speed actuator
before ending the engine warm-up and verify
that the engine speed is changed.
No
Replace the idle
speed actuator
Yes Proceed to next step.
6
Verify that the coolant temperature sensor is
normal.
No Replace
Yes Replace the ECU.
7
Run the engine at idle speed until the coolant
temperature reaches its normal range in order
to verify that the ignition advance angle is
normal.
No Inspect other items
E-74
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