P08B0

What it means

P08B0 means the transmission or powertrain control unit has seen a voltage that is too high on the circuit for neutral position sensor B. The signal sits above the expected range, which usually points to an open circuit, a short to voltage or a faulty sensor. Exactly how the sensor works and where it is fitted depends on the vehicle and gearbox type.

Symptoms

• Warning light on, possibly with a gearbox or transmission fault message
• Engine will not crank or the starter is inhibited in Park or Neutral
• Engine cranks in gear, or the start/stop system behaves oddly
• Harsh, delayed or erratic gear engagement
• Gear position shown incorrectly on the dash
• Gearbox stuck in limp mode or a fixed gear

Possible causes

• Open circuit or high resistance in the sensor signal or ground wirelikely
• Faulty neutral position sensor B or integrated gear selector switchlikely
• Corroded, loose or damaged connector terminals at the sensor or control unitlikely
• Signal wire shorted to a voltage supplypossible
• Selector linkage or cable out of adjustment, giving an implausible position signalpossible
• Faulty transmission or powertrain control unit, or an outdated calibration known to affect this circuitrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including gear position and battery voltage.
2. Check the battery and charging voltage, as low or unstable supply can cause false circuit faults.
3. Inspect the sensor, its wiring and connector for damage, water ingress, corrosion, bent pins or chafing.
4. With a scan tool, watch the live neutral or gear position data while moving the selector through each position and see whether the signal follows or stays fixed.
5. Check the selector cable or linkage adjustment and confirm the selector position matches what the gearbox reports.
6. Using the manufacturer wiring diagram, measure the reference supply, signal and ground at the sensor connector, with the connector unplugged.
7. Test the signal wire for a short to voltage and for continuity back to the control unit.
8. Check for applicable software updates or technical bulletins for the model once wiring and the sensor are proven good.

How to fix

• Repair or replace damaged wiring and fix any short to voltage or open circuit.
• Clean or replace corroded connectors and terminals, and secure them properly.
• Replace the neutral position sensor or gear selector switch if it fails testing.
• Adjust or repair the selector cable or linkage and set it up to the manufacturer procedure.
• Update the control unit calibration only if an outdated calibration is a documented cause, or replace the control unit if it is proven faulty.

Can I keep driving?

Nearby codes

• P08AFGenericNeutral Position Sensor B Circuit Low
• P08B1GenericNeutral Position Sensor B Circuit Intermittent/Erratic