P0703 Code: Brake Switch B Circuit
🟠 Moderate severity · drivable
You can keep driving, but check that your brake lights still work, since a faulty brake switch can leave them off.
What P0703 means
The brake switch has two sets of contacts. Circuit B is the second set, and the computer is not seeing the signal it expects. The transmission uses this signal to unlock the torque converter when you press the brakes.
Symptoms
- Check engine light is on
- Brake lights may not come on
- Cruise control may not work
- Torque converter may not unlock when braking
Common causes
- most common: Faulty brake switch
- common: Misadjusted brake pedal switch
- common: Damaged wiring or loose connector at the brake switch
- less common: Blown fuse for the brake light circuit
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Check brake light bulbs and fuses first | Yes | $5–20 |
| Adjust or replace the brake switch | Yes | $20–80 |
| Repair damaged wiring or connector terminals | Mechanic | $80–250 |
Frequently asked questions
Can I drive with a P0703 code?
Yes, but first confirm your brake lights work. If they don't, fix the switch right away, since drivers behind you need to see your brake lights.
What does brake switch B mean?
The brake switch has two circuits inside it. Circuit B is a second set of contacts that reports brake pedal position to the transmission computer and cruise control.
How much does it cost to fix a P0703?
Usually $20–$80 for a new brake switch, plus a bit more if wiring needs repair. Many drivers can replace the switch themselves.
Related codes
P0719
P0719 Code: Brake Switch B Circuit Low
P0724P0724 Code: Brake Switch B Circuit High
P0700P0700 Code: Transmission Control System Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.