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 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) 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. Connect the timing light to the service loop (white tape) (A).






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 camshaft timing Cam Chain Removal. If the camshaft timing is OK, update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM, then recheck. If the system works properly, and the PCM was substituted, replace the original PCM Service and Repair.

11. Disconnect the HDS and the timing light.