Ignition Timing: Testing and Inspection

Ignition Timing Inspection

1. Connect the HDS to the DLC.

2. Turn the ignition switch to ON (II).

3. Make sure the HDS communicates with the vehicle and the ECM/PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.

4. Check for DTCs Initial Inspection and Diagnostic Overview. If a DTC is present, diagnose and repair the cause before continuing with this test.

5. Start the engine. Hold the engine speed at 3,000 rpm with no load ( in P or N (A/T model) or neutral (M/T model)) until the radiator fan comes on, then let it idle.

6. Check the idle speed Testing and Inspection.

7. Jump the SCS line with the HDS.

8. Free the service loop from the wire harness, then connect the timing light to the service loop.






9. Aim the light toward the pointer (A) on the cam chain case. Check the ignition timing under a no load condition (headlights, blower fan, rear window defogger, and air conditioner are turned off).









10. If the ignition timing differs from the specification, check the cam timing. If the cam timing is OK, update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM, then recheck. If the system works properly, and the ECM/PCM was substituted, replace the original ECM/PCM ECM/PCM Replacement (A/T).

11. Disconnect the HDS and the timing light.