Some Mercedes V-6 and V-8 M272 / M273 engines are prone to a failure of the balance shaft sprocket or idler gear sprocket. What happens is the timing chain wears the softer metal on the sprocket down and in turn slack is developed in the chain. The timing chain tensioner is able to compensate for the slack, however when this happens it causes the right bank camshafts to go out of time slightly. At first the only indication will be a check engine light with one or more of the following fault codes.
-1200 Constant adjustment of exhaust camshaft of right cylinder bank in direction ‘Retarded’ (P0017)
-1208 Constant adjustment of intake camshaft of right cylinder bank in direction ‘Retarded’ (P0016)
These faults will return immediately after starting the engine.
As the problem gets worse the chain tensioner will no longer be able to compensate for the slack and a chain rattle will develop in the engine. After a certain point there is too much metal that has been deposited in the engine and the cylinder head camshaft bearing journals will get scored and the engine will need to be replaced so it is a good idea to get this repaired soon after the first warning which is the check engine light with fault codes P0016 and P0017.
Unfortunately the fix is to remove the engine and replace the balance shaft / idler sprocket and a few other parts that are required per the Mercedes Service Bulletin S-B-03.30/08i
Import Performance can help. This repair typically runs about $3,500 parts and labor. The dealership is well over $5,500 for the same repair. We use only OE Mercedes parts with this repair.
The good news is the balance shaft and idler sprockets have been updated with a stronger metal and the failure will not reoccur. Our warranty is 3 year 36,000 miles nationwide.
Below are a few images of the repair process.