← Back to list

2009 Mercedes E550 P2090 Code: No Performance Issues, Diagnosis Tips & Solutions

Model: Mercedes Fault Code: P2090 Posted: 2020-09-06 15:46

My 2009 Mercedes E550 is consistently throwing a P2090 fault code (B Camshaft Position Actuator Control Circuit Low Bank 1), despite no noticeable performance issues. I've reset the code three to four times, and it returns every time—definitely not a temporary glitch. I’ve ruled out oil-related problems: the engine oil was changed 2,000 miles ago, and pressure readings are within normal range. I also replaced all camshaft position sensors (magnets) as a precaution, but that did not resolve the issue. The ECM was previously replaced by a Mercedes dealership around 10,000 miles ago due to another problem, so it's unlikely to be faulty. An independent mechanic checked the timing chain about 10,000 miles ago and confirmed no stretch or wear. Given that there are no drivability symptoms, what could be causing this persistent P2090 code? What’s a reliable starting point for diagnosing this issue? Are there known common causes related to wiring, sensors, or actuator circuits in the 2009 E550 model?

Related fault codes
P2090
Comments (5)
Anonymous 2022-07-19 19:19

Hi there! I'm experiencing a very similar situation with my 2008 Mercedes GL500 (Australia). The P2090 code randomly appears during drives and then disappears—sometimes for days. It doesn't affect performance, but it's quite frustrating. I suspect it might be related to a faulty sensor or wiring. Any advice or insights would be greatly appreciated!

Anonymous 2022-07-19 21:04

The issue was ultimately the ECU itself. After extensive troubleshooting, I had to convince the dealership to replace it under warranty. It resolved the P2090 code completely—no performance issues at all, just a persistent warning light. This wasn't an easy diagnosis and took months. Hopefully, you don’t end up in that position. The good news is that my car ran perfectly otherwise.

Anonymous 2022-07-20 06:45

Thanks for the input! I'll have my mechanic go through a full sensor and wiring check. I'm hoping it's something minor, like a loose connection or intermittent signal. Just wanted to know if there are any known diagnostic paths or common failure points in this model before taking it to a shop.

Anonymous 2022-07-20 07:22

I didn’t get specific diagnostics from anyone—our conversation focused on camshaft sensors, crankshaft position sensor, and wiring. Nothing conclusive came of it. The problem was extremely intermittent. I ended up going back to the dealership because they had better tools for electrical troubleshooting. One known issue in these vehicles is a leaking oil seal that can seep into the wire harness near the ECU, causing short circuits or signal interference—this might be what happened to me. If your mechanic isn’t experienced with sensor and wiring diagnostics, consider having them check the harness connections carefully. A faulty camshaft position actuator circuit could stem from such a leak. Sorry I couldn't offer more help—I hope it works out for you!

Anonymous 2022-07-20 07:58

Thanks for sharing! I just received a new camshaft position sensor today—now I'm waiting to see how it performs after installation. It's frustrating that many mechanics only do 'check, replace, check again' without deeper diagnostics. I’m starting with the most affordable and common components first: sensors, wiring harnesses, and connectors. Hopefully, this helps others facing similar issues. I’ll update this thread once I know the outcome—whether it’s fixed or not! Haha.