DTC P0038: Rear Ho2S Heater Circuit High: Condition
WARNING: This page is about a different car, the 2002 Mazda Protege5 and 2002 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when PCM detects high input voltage from ground side of rear HO2S heater circuit after PCM turns HO2S heater circuit on. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:
- PCM malfunction.
- Rear HO2S malfunction
- Short to power between rear HO2S and PCM.
- Shorted rear HO2S or PCM.