Intermittent P0016 and P0018 Fault in 2006 Mercedes R350 SE A 4Matic - Possible Sensor or Wiring Issue?
Hello everyone, I own a 2006 Mercedes-Benz R-Class (R350 SE A, 4Matic), with approximately 65,000 miles on the odometer and a petrol V6 engine. About two months ago, the engine warning light activated unexpectedly. My vehicle is equipped with a satnav system that displays stored engine trouble codes. It showed both P0016 and P0018 — codes related to the right-hand bank of the camshaft sensors (as per standard OBD-II interpretations). I took the car to my local Mercedes-Benz dealer, which I typically avoid due to high repair costs. Their diagnostic tool recorded: > Code 120-8: Constant adjustment of intake camshaft on the right cylinder bank in a 'rearward' direction (P0016) — STORED. They indicated they could not identify the root cause without removing the engine and inspecting the mechanical components. Possible issues include a faulty camshaft tensioner, a slipped drive chain, or other internal wear. The quoted repair cost was extremely high — reportedly requiring a lottery win to cover. On my way home, I noticed the warning light had turned off — likely due to code clearing. However, this was only temporary. Since then, the behavior has been intermittent: the engine light would come on and stay lit for several days, then go off after a short period (e.g., after a pre-ignition check), remaining off for weeks before reappearing. The most recent incident occurred during a 200-mile motorway journey. The warning light remained on throughout Sunday and Monday, including urban driving. By Tuesday morning, it had turned off and has stayed off since. I’m now considering that this might not be a mechanical failure — rather, an electrical issue or a sensor intermittently sending faulty signals depending on vehicle speed (e.g., motorway vs city driving). If the problem were truly mechanical — such as a slipping drive chain, tensioner failure, or camshaft misalignment — I would expect symptoms like engine misfires, difficulty starting, rough idling, increased fuel consumption, or noticeable noise. So my question is: Is this just a faulty sensor? Or could it be an intermittent wiring fault at the connector or in the harness? Has anyone else experienced similar intermittent P0016/P0018 behavior on their 2006 R-Class or other Mercedes R-Class models? Any insights, experiences, or troubleshooting tips would be greatly appreciated. Best regards, CDK
P0016 and P0018 occurring simultaneously seems unlikely. This is more likely an intermittent wiring issue — either at the sensor connectors or within the harness itself.