Symptom Checks
Check the following items:
- Check the following PID values: DPFEGR, LONGFT 1, LONGFT 2 and VPWR. See appropriate PIN VOLTAGE/PID VALUE CHARTS article. On some models, DPFEGR PID may not be applicable. If DPFEGR PID value is not within .15 volt of Key On Engine Off (KOEO) value, see TEST HE , step 100) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to run lean. If VPWR PID voltage is not 10.5-17.0 volts, check charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If VPWR PID voltage is 10.5-17.0 volts but not within .5 volt of battery voltage, check battery supply to power relay (or CCRM) and VPWR circuit between PCM and power relay or CCRM, and PWR GND circuits. See WIRING DIAGRAMS article.
- Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
- Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
- Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
- Check A/T Torque Converter Clutch (TCC) and/or TCC solenoid for proper operation. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
- Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
- Check for dragging brakes.
- Check engine mechanical condition. Check intake manifold gasket, camshaft and valves and repair as necessary. See appropriate article in ENGINES.
- Ensure engine operates at normal operating temperature. Check for contaminated Mass Airflow (MAF) sensor. Check air intake system. If no problems are indicated, return to SYMPTOM DIAGNOSIS to identify any additional symptoms or see TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article and check for intermittent faults.