P2AAA
Engine Coolant Bypass Valve B Position Sensor Circuit High
Voltage on the engine coolant bypass valve B position sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Signal wire shorted to B+Common
- Open sensorPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Engine Coolant Bypass Valve B Position Sensor
- Wiring Harness
- ECM
P2AAA 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.