OBD-II code · Powertrain (generic)
P01EF Engine Coolant Heater B Control Circuit Performance
Engine Coolant Heater B Control Circuit Performance: the control circuit has an electrical fault.
Is it safe to drive with P01EF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHeater element failed
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Coolant Heater B
Related codes
- P01EBEngine Coolant Heater A Control Circuit Performance
- P01ECEngine Coolant Heater B Control Circuit/Open
- P01EDEngine Coolant Heater B Control Circuit Low
- P01EEEngine Coolant Heater B Control Circuit High
- P01F0Coolant Temperature Relapsed Below Diagnostic Monitoring Temperature
- P01F1O2 Sensor Circuit Bank 1 Sensor 4
- P01F2O2 Sensor Circuit Low Voltage Bank 1 Sensor 4
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.