P0703: The computer found a fault in the brake switch circuit it uses to release the torque converter clutch
Torque converter / brake switch B circuit malfunction
Severity: Severity not verified — if the car runs badly, have it inspected
The sources do not rate urgency, and the brake switch also runs the brake lights, so we treat it as safety-related and do not give do-it-yourself steps. Urgency is not verified.
P0703 in short
P0703 means the computer found a fault in the brake switch B circuit, which the torque converter clutch uses to know when you brake. TroubleCodes.net lists a faulty or misadjusted brake switch, open or shorted wiring and a stop light fault. Brake lights may not work, so have it checked soon.
The brake switch tells the computer when the brake pedal is pressed so the torque converter clutch can release. If that circuit looks wrong, the computer stores P0703.
TroubleCodes.net lists a faulty or misadjusted brake switch, an open or shorted harness, a poor connection and a stop light fault as causes, with the check engine light and a non-working brake light or torque converter clutch as symptoms.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Faulty or misadjusted brake switch
Common general cause- Why it ranks here
- Listed first by TroubleCodes.net.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
Cause 2: Open or shorted wiring or a poor connection at the brake switch
Common general cause- Why it ranks here
- TroubleCodes.net lists the harness and connection.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
Cause 3: Stop light circuit fault
Common general cause- Why it ranks here
- Named by TroubleCodes.net.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Have someone check whether the brake lights come on when you press the pedal.
IfBrake lights do not work
It meansBrake switch or its circuit is suspect; get it checked promptly.
IfBrake lights work
It meansHave the switch circuit tested.
Step 2: Have a shop test the brake switch adjustment, signal and wiring.
Warning:The brake switch is part of the braking system's lighting and cruise-release circuit; wrong adjustment can leave the brake lights on or off.
IfSwitch faulty or out of adjustment
It meansReplace or adjust it.
IfWiring open or shorted
It meansRepair the wiring.
Points to: Open or shorted wiring or a poor connection at the brake switch
Symptoms
- Check engine light on
- Brake lights that do not work Gets more serious: stop and have it checked.
- Torque converter clutch that does not engage
How to fix
This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.
On your vehicle
We don't have reviewed vehicle-specific evidence for P0703 yet. The causes and tests above apply across vehicles.
Related codes
P0703 questions
Can P0703 affect my brake lights?
TroubleCodes.net lists a non-working brake light as a symptom, so check them.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error