OBD-II code · Powertrain (generic)
P00B5 Radiator Coolant Temperature Sensor Circuit Intermittent/Erratic
Intermittent signal from radiator coolant temperature sensor. 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.
Is it safe to drive with P00B5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyConnector loose or corroded
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Radiator Coolant Temp Sensor, Sensor Wiring
Related codes
- P00B2Radiator Coolant Temperature Sensor Circuit Range/Performance
- P00B3Radiator Coolant Temperature Sensor Circuit Low
- P00B4Radiator Coolant Temperature Sensor Circuit High
- P00B6Radiator Coolant Temperature/Engine Coolant Temperature Correlation
- P00B7Engine Coolant Flow Low/Performance
- P00B8MAP - Mass or Volume Air Flow Correlation Bank 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.