P0008 is a somewhat uncommon OBD2 trouble code. It indicates that the crankshaft and camshaft are not synchronized properly, and should be considered a breakdown risk. Driving without addressing P0008 can lead to engine damage and a costly repair.
While P0008 is a generic code (it has the same definition for every OBD2-equipped vehicle), it is almost always observed in vehicles manufactured by GM (and a few Subaru’s).
P0008 Definition: Engine Position System – Performance – Bank 1
This section breaks down the definition of P0008 into its three main parts. Understanding exactly what the code means can aid you in making the right diagnosis.
Engine Position System
The engine position system is responsible for testing the alignment of the crankshaft and camshaft(s). If the alignment is off a little, the engine won’t run well. If it’s off a lot, it won’t run at all.
The crankshaft moves the pistons up and down. The camshaft(s) need to open the intake valve(s) on the intake stroke and the exhaust valve(s) on the exhaust stroke. If the timing is off even just a little bit, it can cause the piston to damage the valves.
The Powertrain Control Module (PCM) has detected that there is an issue with the crank/cam alignment. However, it has not detected an issue with any of the sensors that it uses to monitor crankshaft/camshaft performance.
Bank one is the side of the engine with the first cylinder. P0008 will be, stored in the PCM’s memory and the check engine light is on.
There usually are symptoms associated with P0008. Here are the most common ones:
- Rough running engine
- Increased fuel consumption
- Hard/No start
- Lack of power
- Noise coming from the timing chain
Here are the most common causes of P0008:
- Stretched timing chain
- The timing chain jumped a tooth
- Bad timing chain tensioner
- Bad reluctor ring (on a camshaft or on the crank)
P0008 is a very challenging code to diagnose at home. Almost all of the potential fixes involve opening the engine up. We recommend taking it into a professional shop for diagnosis (which we rarely do).
Check for TSBs
Many GM vehicles have a Technical Service Bulletin on file that detail timing chain issues (particularly the 3.6). You can look them up on the NHTSA website.
Listen for a Stretched Timing Chain
If you hear a slapping sound from inside the timing cover, that would indicate either a bad tensioner or a stretched timing chain. A loose timing chain can also cause the timing chain to jump a tooth.
Check The Reluctor Wheel
The crankshaft reluctor wheel not being aligned with top dead center is one of the most common causes of P0008.
If your vehicle has P0008, you should not drive it. Doing so before having it checked out can potentially cause engine damage. It is a tough code to diagnose at home and is one of the few codes we recommend taking your vehicle to a shop for diagnosis.