2001 Chrysler T&C O2 Sensor Faults: P0132 and P0138 Codes Explained with Fix
My 2001 Chrysler T&C with a flex-fuel 3.3L engine has recently developed check engine light issues, showing persistent codes P0132 and P0138. Originally, I had multiple O2 sensor-related faults including P0134, P1478, P0141, P0140, P0442, and P0455. After replacing both oxygen sensors and installing new spark plugs, all codes were cleared. However, during a short drive the check engine light reappeared with only P0132 and P0138. The upper O2 sensor wire broke in half when removed—this was repaired as part of the sensor replacement process. The vehicle runs better than before but still exhibits inconsistent performance. I’ve checked for blown fuses, verified wiring connections, and reviewed my Chilton’s wiring diagram (which is limited in detail). While the temperature gauge and cruise control previously failed intermittently, they now function normally. I suspect a possible short or circuit issue involving the O2 sensor heater circuits, especially since both sensors are failing simultaneously. I’ve also considered whether the Mass Airflow (MAP) sensor could be at fault—though this seems less likely based on common failure patterns. A diagnostic scan would be needed to confirm MAP vacuum readings. I recently tested by swapping the ASD relay in the fuse box; after clearing codes, the vehicle ran for 3–4 minutes before performance degraded again, especially under idle and low RPM conditions. Acceleration feels sluggish until throttle response improves slightly. After extensive troubleshooting, I discovered that the Powertrain Control Module (PCM) was faulty. The new upstream O2 sensor failed shortly after installation due to PCM malfunction—a known issue in this model. This problem required a dealer visit for diagnosis and repair. Fortunately, the PCM is covered under federal emissions warranty until 100,000 miles, so I avoided paying $1,000 for replacement. This experience highlights that even after replacing sensors, underlying electronic control module issues can cause recurring O2 sensor faults in the 2001 Chrysler T&C. This fix may help others facing similar symptoms.
Could there be a blown fuse in the O2 heater circuit? Has the wiring been properly repaired after sensor replacement? What brand of oxygen sensors were used?