Possible Causes
WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
DTCs P0031 and P0051 will set when heater current is 0.8 amp or less during heater operation (one trip detection logic).
DTCs P0032 and P0052 will set when heater current exceeds 19.7 amps when heater operates (one trip logic detection).
Possible causes are:
- Open or short in heater circuit of A/F sensor.
- Defective A/F sensor heater.
- Defective A/F sensor heater relay.
- Defective ECM.