OBD-II code · Powertrain (generic)
P01B4 Alternative Fuel Rail Temperature Sensor Circuit
Generic electrical fault on alternative fuel rail temperature sensor (CNG/LPG/H2 systems).
Is it safe to drive with P01B4?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor failed
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Alt Fuel Rail Temp Sensor, Sensor Wiring
Related codes
- P01B1Alternative Fuel Tank A Level Sensor Circuit Low
- P01B2Alternative Fuel Tank A Level Sensor Circuit High
- P01B3Alternative Fuel Tank A Level Sensor Circuit Intermittent/Erratic
- P01B5Alternative Fuel Rail Temperature Sensor Performance
- P01B6Alternative Fuel Rail Temperature Sensor Circuit Low
- P01B7Alternative Fuel Rail Temperature Sensor Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.