P0703 on Chevrolet: How to Diagnose & Fix
Brake Switch B Circuit Malfunction
1 Chevrolet model · 1 documented issue · $30-$180 repair
P0703 on Chevrolet by model: symptoms, diagnosis and fix
A recurring issue on 2004-2007 Malibu models is failure of the brake light switch or related stoplamp circuit components, leading to inoperative brake lights, cruise control cancellation problems, or inability to shift out of Park. Some owners also report intermittent brake lamps staying on or not illuminating consistently. Because the stoplamp signal is shared with several systems, a simple switch fault can create multiple confusing symptoms at once.
Common Symptoms
- Brake lights inoperative
- Cannot shift out of Park
- Cruise control not working
- Brake lights stay on
- Intermittent stoplamp operation
- Shift interlock malfunction
How to Fix
Diagnosis should verify brake lamp operation, switch adjustment, and voltage in and out of the brake pedal switch. If the switch is intermittent or out of adjustment, replacement is straightforward and often resolves cruise and shift-lock complaints. Also inspect the fuse, lamp sockets, and shift interlock operation to rule out secondary wiring issues.
Sources for this issue (1)
P0703 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0703 mean on a Chevrolet?
P0703 stands for "Brake Switch B Circuit Malfunction." This code means the engine/transmission computer detected an out-of-range or implausible signal from the brake switch (circuit B). The brake switch tells the PCM/TCM when the brakes are applied, which affects cruise control, torque converter lockup, and certain shift and idle strategies. A faulty signal can cause issues like cruise control not working, harsh shifts, or the converter not unlocking. On Chevrolet it is documented across 1 model: Malibu.
What are the most common causes of P0703?
The most common causes of P0703 are: Faulty brake light switch, Misadjusted brake switch, Open or shorted brake switch wiring, Corroded or loose connector at the switch, Blown brake circuit fuse, PCM/TCM input fault. The specific cause varies by vehicle.
How much does it cost to fix P0703 on a Chevrolet?
Published repair estimates on Chevrolet range from $30 to $180 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0703 on a different make?
View P0703 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.