P2B8E
Intake Air O2 Sensor Heater Control Circuit High Bank 1
Voltage on the intake air O2 sensor heater control line on bank 1 is above the expected window. Wire shorted to B+ or heater element open.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on after several drive cycles
- Slightly increased fuel consumption during cold start
- Delayed entry into closed-loop fuel control
- Failed emissions inspection (lambda readiness)
Common causes
Ordered by how often each turns out to be the cause.
- Heater wire shorted to B+Common
- Open heater elementPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Intake Air O2 Sensor B1
- Intake Air O2 Sensor Heater B1
- Wiring Harness
- ECM
P2B8E 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.