GM 3.6L Timing Chain Diagnosis

Search for any Technical Service Bulletins (TSBs) related to the diagnostic trouble codes (DTCs) set.

• Make sure to search for TSBs using the specific vehicle make and model

• Follow up on any TSBs found before continuing diagnosis

Check if any related DTCs are stored that may help in diagnosis

• Camshaft and crankshaft position sensor issues may skew the engine control module (ECM) from accurately determining cam/crank correlation,this can cause false correlation DTCs to set, always repair these DTC's before diagnosing timing chain correlation issues

• Variable valve timing issues can cause the mechanical engine timing to be off, if VVT DTCs are stored determine cause of issue before proceeding with diagnosis of correlation DTCs

Compare the timing chain correlation DTC or DTCs retrieved from your vehicle with the chart below to determine what cylinder bank has the issue on your engine, bank 1, bank 2 or both cylinder banks

Inspect the VVT system and components for proper operation.

• Inspect VVT system for proper operation, paying close attention to the cylinder bank and camshaft setting Cam/crank correlation DTCs

• Check VVT solenoids and camshaft phasers for sticking and affecting mechanical engine timing

• For more information see: What is Variable Valve Timing (VVT)

Verify the mechanical engine timing

• Mechanical engine timing can be checked manually or electronically with the use of a labscope

• To manually check timing follow service information to remove the engine timing cover to gain access to timing marks and camshafts

• For more information on how to check timing with a lab scope see: How to Test GM 3.6L Timing Chain