Timing chain
Definition
A timing chain does the same job as a timing belt but runs in oil inside the engine with a hydraulic tensioner and plastic guide rails; it is designed to last the engine's life but in practice many stretch. Stretch comes from pin and bushing wear accelerated by extended oil change intervals, low oil level and cold-start load; worn guides shed plastic that blocks the oil pickup. Symptoms are a rattle for the first seconds after a cold start (tensioner bled down), a constant whirring or rattling at idle, and cam/crank correlation codes as the cam timing retards. Measure stretch with a scan tool's cam deviation value or by checking the tensioner plunger extension; replacing requires chain, tensioner, guides and sprockets together. Codes: P0016-P0019 (correlation), P0008/P0009 (engine position performance), P0011-P0014 (cam timing out of range), P0340/P0345 (cam sensor implausible).
Codes often stored
- P0008Engine Position System Performance
- P0009Engine Position System Performance
- P0011"A" Camshaft Position – Timing Over-Advanced or System Performance (Bank 1)
- P0014"B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
- P0016Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A)
- P0017Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)
- P0340Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor)