Brake Temperature Sensor 1 - Voltage Out of Range
The brake temperature sensor is reporting a voltage that is too high or too low.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The brake temperature sensor measures the heat of the brakes. If it reports a voltage reading that's way too high (greater than 5 volts) or too low (less than 0.5 volts), the system thinks the sensor is faulty.
What the computer is actually seeing
The engine control module (ECM) expects the brake temperature sensor to signal a voltage between 0.5 and 5 volts depending on the temperature. Outside this range, it triggers a fault code.
What a healthy reading looks like
Expected voltage from the sensor should be between 0.5 volts (cold) to around 4.5 volts (hot).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the brake temperature sensor wiring for damage, shorts, or corrosion. Repair as necessary. Decision: Is wiring intact?
- 22. Check the connector for the brake temperature sensor for corrosion or loose connections. Repair/replace if needed. Decision: Is the connector secure and clean?
- 33. Measure the voltage at the brake temperature sensor connector with the ignition on (engine off). Voltage should be between 0.5 and 5 volts. Decision: Is voltage within range?
- 44. If the voltage is out of range, replace the brake temperature sensor. If it’s in range, suspect a bad ECM. Decision: Replace sensor, or test ECM?
Common causes
- Faulty brake temperature sensor
- Wiring issues (shorts or opens)
- Bad connector at sensor or ECM
- ECM software issue
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's moderately safe but may lead to performance issues or increased brake wear. Fix it soon.
Will this code come back after clearing?
Yes, if the underlying issue isn't fixed, it will likely recur.
Why does this code sometimes pair with SPN 3945?
SPN 3945 relates to a second brake temperature sensor; issues can affect both.
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