P25C6: Brake Booster Temperature Sensor A Circuit Low
The booster temperature signal is below the lower diagnostic threshold. Typical causes are a shorted sensor element or a short to ground in the harness.
What P25C6 means
P25C6 is a generic OBD-II chassis code in the ABS & brakes group. In plain English: the computer sees a voltage on that circuit that is lower than it should ever be — often a short to ground, an open, or a failed sensor.
- Check engine light
- Usually on
- Emissions-related
- No
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Common causes
- 01Internal short in the sensor elementMost likely
- 02Sensor signal wire shorted to groundPossible
- 03Connector pins corroded - high contact resistanceLess likely
Can I drive with P25C6?
Drive carefully and get it checked soon.
Normal hydraulic braking usually still works, but ABS, stability control or brake assist may be off. Leave extra stopping distance, especially on wet or icy roads. If the pedal feels soft or the red brake light is on, stop driving.
Why we rate it urgent
- ABS or brake assist may be disabled
- Turns on the check engine light
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P25C6
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P25C6. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Check for related codes first
Look for C05B3, C0579. Related codes often share a cause; a circuit or sensor code usually needs fixing before a performance code like this one.
- 3
Test the circuit
Inspect the wiring and connector at the electric brake booster and temperature sensor for damage, corrosion or chafing. With a multimeter, check supply voltage, ground and signal against the specifications in the service manual for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Internal short in the sensor element; sensor signal wire shorted to ground; connector pins corroded - high contact resistance. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P25C6 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Hard
- Good DIY job?
- Usually a shop job
Involved testing or major parts. Most owners use a shop.
Parts and systems involved
- Electric brake booster
- Temperature sensor
- Wiring harness
P25C6 FAQ
What does P25C6 mean?
P25C6 means “Brake Booster Temperature Sensor A Circuit Low”. The booster temperature signal is below the lower diagnostic threshold. Typical causes are a shorted sensor element or a short to ground in the harness.
Is P25C6 serious? Can I keep driving?
We rate P25C6 as urgent severity. Drive carefully and get it checked soon. Normal hydraulic braking usually still works, but ABS, stability control or brake assist may be off. Leave extra stopping distance, especially on wet or icy roads. If the pedal feels soft or the red brake light is on, stop driving.
What causes P25C6?
The most common causes, from most to least likely: Internal short in the sensor element; Sensor signal wire shorted to ground; Connector pins corroded - high contact resistance. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P25C6?
Typical labor is about $125–$440 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P25C6 myself?
DIY difficulty is hard. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P25C6 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.