Mercedes E320 (2001) with P0173, P0170, P0442 Codes: Causes and Solutions
I own a 2001 Mercedes E320 with 200,000 miles and excellent mechanical condition. After recently having my oil changed, I began receiving the following OBD2 diagnostic codes: P0173, P0170, and P0442. I'm trying to determine whether these codes are related to faulty oxygen sensors or a clogged air filter. Any technical insights or troubleshooting steps would be greatly appreciated. Thanks for your help.
Since recent work was performed under the hood, it's worth checking vacuum hoses—especially those connected to the EVAP system—for any loose or disconnected fittings. Code P0442 indicates a small evaporative emission leak, which can directly cause the fuel trim issues shown by P0170 and P0173.