P01B8
Alternative Fuel Rail Temperature Sensor Circuit Intermittent/Erratic
Generic OBD-II
Common symptoms
What you'll notice
- Check the wiring connections and harness for any loose or damaged wires
- Inspect the fuel rail temperature sensor for any damage or corrosion and replace if necessary
- Clean the fuel rail and injectors to ensure proper fuel delivery
- Reset the vehicle's ECU (Engine Control Unit) to clear any stored error codes and assess if the issue persists
Common causes
Most likely first
- Faulty or loose connection in the wiring harness of the alternative fuel rail temperature sensor
- Malfunctioning alternative fuel rail temperature sensor
- Damaged or corroded terminals in the connector of the alternative fuel rail temperature sensor
- Issues with the engine control module (ECM) or powertrain control module (PCM) that are causing erroneous readings
- Problems with the fuel system, such as clogged fuel lines or a faulty fuel pump relay
How to diagnose & fix
Work through it in order
- Check engine light illuminated on the dashboard
- Decreased fuel efficiency
- Engine misfires or runs rough
- Difficulty starting the vehicle
- Stalling or hesitation while driving
Read & clear P01B8 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.