Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Inspect the engine front cover area, or review the service history of the vehicle for any recent repairs involving the timing chain, timing chain tensioner, camshaft, crankshaft, camshaft actuator, or sprockets.
- If recent repairs were made, refer to Timing Chain and Sprockets Replacement (LC9/LMG/LY2/LY5) or Timing Chain and Sprockets Replacement (LY6/L76/L92) , and inspect the timing chain, timing chain tensioner, and both sprockets for proper timing alignment or indexing.
- Monitor the engine oil pressure parameter value with a scan tool. The engine oil pressure must be at or above the minimum hot oil pressure values. Refer to Engine Mechanical Specifications (RPO LY2 VIN C)
or Engine Mechanical Specifications (RPO LMG VIN 0)
or Engine Mechanical Specifications (RPO LY5 VIN J)
or Engine Mechanical Specifications (RPO LC9 VIN 3)
or Engine Mechanical Specifications (RPO L76 VIN Y)
or Engine Mechanical Specifications (RPO LY6 VIN K)
or Engine Mechanical Specifications (RPO L92 VIN 8)
.
- If the engine oil pressure is low, correct the cause of the low oil pressure condition first.
- Remove the engine front cover, refer to Engine Front Cover Replacement (RPOs LC9/LMG/LY2/LY5)
or Engine Front Cover Replacement (RPOs LY6/L76/L92)
and inspect the timing chain, timing chain tensioner, and sprockets for wear or damage. Refer to Timing Chain and Sprockets Cleaning and Inspection
.
- If any components are worn or damage, replace as necessary. If the all the components test normal, replace the CMP actuator assembly.
IMPORTANT:
Incorrect engine oil viscosity, aftermarket engine oil additives, or engine oil that is overdue for changing, can greatly affect the performance of the camshaft actuator.