P2B5B
Engine Coolant Flow Control Valve Control Circuit High
The engine coolant flow control valve reports a control circuit high condition. Coolant routing between engine and radiator branches cannot be commanded as expected.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to B+Common
- Open valve motorPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Engine Coolant Flow Control Valve
- Wiring Harness
- ECM
P2B5B 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.