Cold Start Variable Cam Timing Monitor (2008 My And Beyond)
If the VCT cam phasing is used during a cold start to improved catalyst heating, the VCT system is checked functionally by monitoring the closed loop cam position error correction. If the proper cam position cannot be maintained and the system has an advance or retard error greater than the malfunction threshold, a cold start emission reduction (CSER) VCT control malfunction is indicated (P052A/P052B (Bank 1), P052C/P052D (Bank2). This test is the same test that was used previously for monitoring the VCT system under Comprehensive Component Monitoring requirements.
CSER VCT TARGET ERROR CHECK OPERATION
| DTCs | P052A - Cold start camshaft position timing over-advanced (Bank 1) P052B - Cold start camshaft timing over-retarded (Bank 1) P052C - Cold start camshaft timing over-advanced (Bank 2) P052D - Cold start camshaft timing over-retarded (Bank 2) |
| Monitor execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | |
| Monitoring Duration | 5 seconds |
TYPICAL CSER VCT TARGET ERROR ENTRY CONDITIONS
| Entry Condition | Minimum | Maximum |
| VCT control enabled and commanded to advance or retard cam during CSER | n/a | n/a |
| Time since start of CSER cam phase monitoring | 60 seconds |
TYPICAL CSER VCT TARGET ERROR MALFUNCTION THRESHOLDS
| CSER Response/target error - VCT over-advance: 11 degrees CSER Response/target error - VCT over-retard: 11 degrees CSER Response/Stuck Pin - 10 degrees phasing commanded, and not seeing at least 2 degrees of movement. |