Torque Converter/Brake Switch B Circuit High
The P0724 code indicates that the powertrain control module (PCM) has detected a high voltage signal from the brake switch B circuit. This switch is part of the torque converter clutch (TCC) system and signals when the brake pedal is pressed. A high voltage condition typically means the circuit is shorted to power or the switch is stuck closed, causing the PCM to see a constant brake-on signal. This can prevent the torque converter from locking up, affecting fuel economy and transmission operation.
01. Most Common Causes
- Faulty brake switch B (stuck closed or internal short)
- Short to voltage in the brake switch B circuit wiring
- Corroded or damaged connector at the brake switch
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Cruise control inoperative
- Torque converter not locking up (poor fuel economy)
- Brake lights may stay on or not work properly
03. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0724 is present. Check freeze frame data.
Step 2: Inspect brake switch B and its connector for damage, corrosion, or misadjustment.
Step 3: Using a multimeter, check for voltage at the brake switch B signal wire with key on. Should be low (0V) when brake released and high (12V) when pressed. If high constant, suspect short to power or stuck switch.
Step 4: Disconnect brake switch and check if voltage drops. If not, repair short in wiring. If voltage drops, replace brake switch.
Step 5: Clear codes and test drive to confirm repair.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short distances, but the torque converter may not lock up, reducing fuel economy and potentially causing transmission overheating. Also, cruise control may not work. Have it diagnosed soon.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor. A brake switch costs $20-$50, and labor is about $30-$100 depending on the vehicle.