P2AAB
Engine Coolant Bypass Valve B Position Sensor Circuit Intermittent/Erratic
The engine coolant bypass valve B position sensor signal drops out or jumps intermittently. Loose connector or noisy ground.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor connector not seatedCommon
- Noisy ground referencePossible
- Connector with intermittent contact under vibrationLess likely
Parts involved
- Engine Coolant Bypass Valve B Position Sensor
- Wiring Harness
- ECM
P2AAB 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.