P0038
HO2S Heater Control Circuit High (Bank 1 Sensor 2)
The heater control line for the upstream bank 1 oxygen sensor reads above the expected voltage, typical of a short to supply.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Heater wire shorted to supplyCommon
- Connector pins corroded - high contact resistanceLess likely
- Supply wire pinched against B+ sourceLess likely
Parts involved
- Oxygen Sensor Heater
- Sensor Wiring
P0038 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.