Powertrain
generic / SAE
P00B4
Radiator Coolant Temperature Sensor Circuit High
Radiator coolant temperature sensor signal voltage above expected range. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number– / B4
Possible causes
- Signal wire open high
- Connector pins corroded - high contact resistance low
- Supply wire pinched against B+ source low
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 40–250 €
- Estimated time: 0.3–1.5 h
- Component: radiator coolant temp sensor
- Component: sensor wiring
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012