Circuit/System Testing

Ignition ON, observe the scan tool DTC information. Verify there are no other DTCs set.
- If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
Engine idling, observe the MAP sensor parameter. The reading should be between 19-42 kPa (2.7-6 PSI).
- If not within the specified range, refer to DTC P0106 , or DTC P0107 or P0108 .
Ignition OFF, verify that none of the conditions listed below exists:
- Inspect the air induction system for modified, damaged, leaking, or restricted components.
- Inspect the crankcase ventilation system for improper operation. Refer to Crankcase Ventilation System Inspection/Diagnosis .
- Inspect the vacuum hoses for splits, kinks, and improper connections.
- Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.
- Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to Symptoms - Engine Exhaust .
- Test the fuel injectors for improper operation. Refer to Fuel Injector Diagnosis (CH47976) , Fuel Injector Diagnosis (J39021 or Scan Tool) .
- Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Test for excessive fuel in the crankcase due to leaking injectors.
- Test the ignition system for improper operation. Refer to Electronic Ignition System Diagnosis .
If all the above conditions test normal, test the engine for any mechanical conditions that could alter the flow into the combustion chamber. Refer to Symptoms - Engine Mechanical (L76, L77) .