P0703: Torque converter/brake switch B: circuit fault
The ECU is not getting a proper signal from the brake pedal switch used by the automatic gearbox; the switch itself is usually to blame.
| Code | P0703 |
|---|---|
| System | Engine and transmission |
| Group | P07xx, Transmission |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0703 means
The brake pedal switch tells the control units when you brake. Besides lighting the brake lights, it is used to unlock the torque converter in an automatic gearbox, release the selector from P and cancel cruise control. This code means the signal on circuit B of that switch does not make sense.
Most common causes
- Brake pedal switch out of adjustment or faulty
- Loose switch connector
- Blown brake light fuse
- Damaged switch wiring
- ECU fault (uncommon)
Symptoms
- Brake lights not working or staying on
- Selector will not come out of P
- Cruise control not working
- Jerky feel when braking to a stop
Can you drive with P0703?
With care You can drive with care, but check the brake lights as soon as possible: if they do not work, drivers behind you will not see you braking.
Open the bonnetthe in-depth explanation
How to check it
Ask someone to watch the brake lights while you press the pedal: if they do not light, or stay on when you release it, the pedal switch is the first suspect.
How to read and clear P0703 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0703 with its description and whether it’s confirmed, pending or permanent.
This code is usually stored by the gearbox control unit. If the car reports it over standard OBD, you read it for nothing with FREE; to read it straight from the gearbox control unit, with its description and clearing, you need PRO.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P0700 Transmission control system: fault detected
- P0701 Transmission control system: range/performance
- P0702 Transmission control system: electrical fault
- P0704 Fault in the clutch pedal switch
- P0705 Transmission range sensor: circuit fault
- P0706 Transmission range sensor: range/performance
- P0707 The gearbox position sensor gives a lower signal than normal
- P0710 Transmission fluid temperature sensor: circuit fault
- P0711 Transmission fluid temperature sensor: range/performance
- P0712 Transmission fluid temperature sensor: circuit low
- P0713 Transmission fluid temperature sensor: circuit high
What does code P0703 mean?
The brake pedal switch tells the control units when you brake. Besides lighting the brake lights, it is used to unlock the torque converter in an automatic gearbox, release the selector from P and cancel cruise control. This code means the signal on circuit B of that switch does not make sense.
Can you drive with P0703?
You can drive with care, but check the brake lights as soon as possible: if they do not work, drivers behind you will not see you braking.
How do you clear P0703?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0703 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
