Fault codeP0703

MODERATE

Torque Converter/Brake Switch B Circuit Malfunction

What this code means

Torque Converter/Brake Switch B Circuit Malfunction.

P0703 is a generic code: it means the same thing on every make. P0703 belongs to family P07xx — Transmission. Its page explains how to read a code and groups all its codes by part.

Type of fault

The control unit has detected an electrical anomaly on this circuit without saying exactly which. Diagnosis starts with a visual check of the wiring and connector, then measuring the component — resistance, supply, ground — with a multimeter.

Brake switch (gearbox input)

The brake switch tells the gearbox control unit when you press the brake pedal. On automatic gearboxes it unlocks the gear selector from Park and releases the torque converter clutch as you slow down.

What you notice

Selector stuck in Park, the engine shuddering or stalling when stopping, brake lights that stay on or do not light.

How to check it

Check the brake lights, then the switch on the pedal: its adjustment, its connector and its plunger. It is an inexpensive part, often simply clipped behind the pedal.

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
7Transmission
03P0703