Possible Causes
WARNING: This page is about a different car, the 2003 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0037 is set when heater current .25 amp or less while heater is operating. DTC P0038 is set when heater current exceeds 2 amps while heater is operating. Possible causes are:
- Open or short in HO2S heater circuit.
- Defective HO2S heater.
- Defective ECM.