What are the common causes of P0703?

An open or short in the brake switch B circuit. A worn or faulty brake switch B. Corroded brake switch B connector terminals. A misadjusted brake pedal position sensor.

Check battery voltage and the brake switch B feed. Inspect the brake switch B connector and wiring. Test brake switch B continuity through pedal travel. Compare the brake pedal position sensor on a scan tool. Replace brake switch B if it does not change state. Clear the code and retest.

P0703

Brake Switch B Circuit

System: Transmission (P code)
Lamp: Check Engine Light
Category: Powertrain - Transmission

What it means

P0703 means Brake Switch B Circuit.

Where it lives

For P0703, the circuit described runs through the switch. The description of P0703 reports a fault at the switch.

Check these first

An open or short in the brake switch B circuit
A worn or faulty brake switch B
Corroded brake switch B connector terminals
A misadjusted brake pedal position sensor

What to do next

Check battery voltage and the brake switch B feed
Inspect the brake switch B connector and wiring
Test brake switch B continuity through pedal travel
Compare the brake pedal position sensor on a scan tool
Replace brake switch B if it does not change state
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.