TransmissionMinor✅ DIY Friendly

P0703

Q: What does OBD2 code P0703 mean?

P0703 means: Brake Switch B Circuit Malfunction. A secondary brake switch circuit, used by the transmission control system to detect brake pedal application, has a fault.

Brake Switch B Circuit Malfunction

A secondary brake switch circuit, used by the transmission control system to detect brake pedal application, has a fault.

SeverityMinor

CategoryTransmission

Est. Repair Cost$60-$150

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›Faulty brake switch
›Misadjusted switch
›Damaged wiring

⚠️ Symptoms

›Check engine light
›Possible issues with torque converter lockup or shift quality
›Cruise control may be affected

✅ How to Fix — Step by Step

Step 1:Test brake switch operation
Step 2:Check switch adjustment
Step 3:Replace switch if faulty

🔧 Diagnostic Tools Required

✔OBD-II Diagnostic Scanner
✔Transmission Pressure Gauge
✔ATF Temperature Reader
✔Digital Multimeter
✔Basic Hand Tools

Using the correct diagnostic tools helps identify the root cause of P0703 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: This is often the same physical switch as the main brake light switch, just wired to a second circuit - check both circuits together.

Frequently Asked Questions

What does OBD2 code P0703 mean?+

P0703 stands for Brake Switch B Circuit Malfunction. A secondary brake switch circuit, used by the transmission control system to detect brake pedal application, has a fault.

What causes code P0703?+

Faulty brake switch; Misadjusted switch; Damaged wiring

How do I fix code P0703?+

Test brake switch operation; Check switch adjustment; Replace switch if faulty

How much does it cost to fix P0703?+

Estimated repair cost for P0703 is $60-$150.

Is P0703 DIY-friendly?+

Yes — P0703 is generally DIY-friendly with basic tools.