2004 Toyota RAV4 P2238 Fault: O2 Sensor Bank 1 Sensor 1 Positive Current Control Circuit Low - Diagnosis and Fix
The MIL (Malfunction Indicator Lamp) light came on a few days ago in my 2004 Toyota RAV4 2.0L VVTi petrol engine (UK model). The vehicle continued to drive normally with no noticeable performance issues. The next day, the MIL light turned off and I completed a long journey home without any further symptoms. Upon arriving home, I used an OBD2 code reader and found fault code P2238: 'O2 Sensor Positive Current Control Circuit Low - Bank 1 Sensor 1'. I'm seeking advice on what this error likely indicates — is it due to a wiring issue, a sensor failure, or something else? Given that the car drives normally, should I simply erase the code and monitor for recurrence? Or does this point to a more serious underlying problem requiring immediate attention? Any insights into the most probable cause and recommended troubleshooting steps would be greatly appreciated. Regards, Gary
Gary, it's best to first erase the P223-8 code and monitor for recurrence. If the issue returns, then investigate further. A common cause of this fault is a damaged wiring harness or poor connection at the A/F sensor (Bank 1 Sensor 1). Check for any visible damage in the wiring, especially where it routes near the exhaust system. Also inspect the sensor connector for corrosion or loose connections. This code typically appears when there's a short to ground or an open circuit — either in the wiring or within the oxygen sensor itself.