OBD-II code · Powertrain (generic)
P01B8 Alternative Fuel Rail Temperature Sensor Circuit Intermittent/Erratic
Intermittent signal from alt fuel rail temp sensor. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P01B8?
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
- 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
- P01B5Alternative Fuel Rail Temperature Sensor Performance
- P01B6Alternative Fuel Rail Temperature Sensor Circuit Low
- P01B7Alternative Fuel Rail Temperature Sensor Circuit High
- P01B9Engine Oil Temperature Sensor B Circuit
- P01BAEngine Oil Temperature Sensor B Range/Performance
- P01BBEngine Oil Temperature Sensor B Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.