P0725 — Torque Converter/Brake Switch B Circuit High
Drive with caution — fix soon.
What P0725 means
This code means the transmission control module detected an abnormally high voltage in the torque converter or brake switch "B" circuit, which it relies on to know when to engage or release the torque converter lockup. It's commonly caused by a faulty brake light switch, a problem in the torque converter clutch solenoid circuit, or damaged wiring and connectors. Repairs usually involve testing the switch and circuit and replacing the faulty part, which is often a manageable fix.
Common symptoms
- Check engine light is on
- Torque converter not locking up properly
- Slightly reduced fuel economy
- Brake lights may behave incorrectly
- Odd or harsh shift behavior
Common causes
- Faulty brake light switch
- Torque converter clutch solenoid circuit problem
- Damaged or corroded wiring or connectors
- Short to voltage in the circuit
- Failing transmission control module
Typical repair cost
$100 – $400
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0725 code?
Usually yes, at least for a while, but you may notice the torque converter not locking up and slightly worse mileage. It's best to get it diagnosed soon.
How much does it cost to fix a P0725 code?
Repairs commonly range from $100 to $400. A brake light switch is inexpensive, but a torque converter solenoid or wiring repair can cost more.
Is a P0725 code serious?
It's moderately serious. It mainly affects torque converter lockup and efficiency rather than safety, but it's worth fixing to keep the transmission running smoothly.
Can a brake light switch cause a P0725 code?
Yes. This circuit often ties into the brake switch, so a faulty or misadjusted brake light switch is a common cause of a high-voltage reading here.