P2BB5
Engine Coolant Temperature Sensor 5 Circuit Intermittent/Erratic
The signal of engine coolant temperature sensor 5 drops out or jumps intermittently. Loose connector or noisy ground reference.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Symptoms
- Check engine light on
- Cooling fan runs constantly or not at all
- Cabin heater weak or excessively hot
- Possible long warm-up time or hard cold start
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 Temperature Sensor 5
- Wiring Harness
- ECM
P2BB5 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.