Checking Ignition Timing
- Connect scan tool to OBD-II Data Link Connector (DLC) located below instrument panel, to right of steering column. See Fig 1. Install timing light. Start and warm engine until engine coolant temperature is 176-203°F (80-95°C). Turn lights and accessories off. Put automatic transmission in Park or manual transmission in Neutral.
- Allow engine to idle. Using scan tool, check and ensure engine curb idle speed is within specifications for timing check. See IGNITION TIMING SPECIFICATIONS table. Curb idle speed is automatically controlled by Idle Air Control (IAC) system. If curb idle speed is not as specified, check IAC system. See DTC P0505 test in appropriate SELF-DIAGNOSTICS article. If IAC system is okay, adjust basic idle. See BASIC IDLE SPEED under IDLE SPEED & MIXTURE.CAUTION: MFI system actuator test must be cancelled after basic ignition timing check or test will continue to run for 27 minutes. Driving vehicle under this condition may damage engine.
- Using scan tool, select MFI SYSTEM ACTUATOR TEST, then select item No. 17 (BASIC IGNITION TIMING). Press "Y" and read basic ignition timing value. If basic ignition timing is within specification, go to next step. If basic ignition timing is not within specification, cancel MFI system actuator test and check CKP sensor circuit. See DTC P0335 test in appropriate SELF-DIAGNOSTICS article.
- Cancel MFI system actuator test. Read actual ignition timing value. See IGNITION TIMING SPECIFICATIONS table.