Page 992 - Workshop Manual - Tunland (2017)

04-306 DIAGNOSTICS - ENGINE CONTROL SYSTEM

04 THE ENGINE TURNS OFF WHEN IT COLD IDLES

Fault phenomenon Diagnosis logic Possible reasons
• Electronic throttle fault
• Idle air fuel ratio control
• Intake system
system fault
• Air fuel ratio
• Electronic throttle fault
The engine turns off when it • Electronic throttle valve
• Too low of the compression
cold idles • Too low of the compression pressure
pressure
• Exhaust control system
• ECM
fault
• ECM

Diagnosis Procedure

1 . Check the engine data
(a) Ignition switch: OFF.
(b) Connect the diagnosis tool with the fault diagnosis connector (16 pins) on the lower
left of the dashboard.
(c) Ignition switch: ON, and start the diagnostic tool.
(d) Read the motor data shown on the diagnostic tool.

Check whether the data flow is normal or not.
YES>To step 2.

No >Maintenance related faults.

2 . Perform visual and external check
(a) Observe the rotation status and shaking degree of the engine
(b) At the same time, observe the swing range of the engine tachometer indicator, and
check whether it deviates from the idle target value.
(c) Observe whether it is normal idle jitter or load idle jitter. (Turn on the air conditioner,
light, hanging gear and turn the steering wheel etc.)
(d) Whether the external parts of the motor are normal or not; whether the wire connector
looses or not.

Is the inspection result normal?
YES>To step 3.

No > Exclude the abnormal problem and confirm that the phenomenon no longer
exists.

3 . Check the throttle body
(a) Check whether the throttle has oil and carbon deposition is stuck or not, the air intake
channel around the throttle has oil and carbon deposition or not.
(b) Start the motor, idling rotation.
(c) Use a diagnostic tool, perform the throttle test.
(d) When the diagnostic tool controls the throttle rotation, the motor speed can have high
or low changes simultaneously.