P07B2

What it means

P07B2 is the generic code for a fault in the Park position sensor or switch 'A' circuit, specifically an open circuit. The transmission or powertrain control unit has seen a signal, voltage or resistance from the Park position sensor that suggests a break in the circuit, such as a broken wire or a poor connection. Its exact location and how it works vary by vehicle, and many modern cars with electronic gear selectors use it to confirm Park.

Symptoms

• Engine will not crank or start, or starts only in Neutral
• Gear selector display shows no gear, wrong gear or flickers
• Warning light or message on the dashboard about the transmission or gear selector
• Reversing lights or shift interlock not working correctly
• Transmission stuck in limp mode or Park not engaging or releasing correctly
• Intermittent fault that comes and goes with selector movement or vibration

Possible causes

• Damaged, chafed or broken wiring in the Park position sensor circuitlikely
• Corroded, loose or contaminated connector at the sensor or switch, or at the control unitlikely
• Faulty Park position sensor or switch, or the selector assembly it is built intolikely
• Misadjusted selector linkage or position switch on models that use an adjustable switchpossible
• Low or unstable supply voltage or poor earth to the sensor circuitpossible
• Fault inside the transmission or powertrain control unitrare
• Outdated control unit software where the manufacturer has issued a known correctionrare

How to diagnose

1. Read all stored and pending codes and freeze frame data, noting whether other transmission, selector or network codes are present and if the fault is current or intermittent.
2. Check the battery condition and charging voltage, as low voltage can cause circuit faults and false codes.
3. Visually inspect the sensor or switch wiring and connectors for chafing, heat damage, fluid ingress, corrosion and bent or pushed-out pins.
4. With the live data, move the selector through each position and see whether the Park signal changes as expected and drops out when the wiring or connector is wiggled.
5. Using the manufacturer's wiring diagram, check the circuit for continuity, short to earth, short to voltage and excessive resistance, with the connectors disconnected.
6. Check the supply voltage and earth at the sensor connector against the specification for that model.
7. Check the selector linkage and switch alignment where it is adjustable, following the procedure for that model and transmission.
8. Check for any software updates or technical bulletins for the vehicle and transmission.

How to fix

• Repair or replace damaged wiring, and secure it clear of heat and moving parts.
• Clean or replace corroded or damaged connectors and terminals, and fix any fluid leaks that are contaminating them.
• Replace the Park position sensor, switch or selector assembly if it fails testing, following the model procedure.
• Adjust the selector linkage or position switch to the specified setting.
• Repair supply or earth faults found in the circuit.
• Update or replace the control unit only if testing confirms it is faulty or a known software fix applies.

Can I keep driving?

Nearby codes

• P07B1GenericTransmission Friction Element H Stuck On
• P07B3GenericTransmission Park Position Sensor/Switch A Circuit Low