P25C4
- Powertrain
- Manufacturer-specific
Get it looked at now
Driving may cause further damage or leave you stranded. Arrange service promptly rather than waiting.
Brake Booster Temperature Sensor A Circuit
This code is in our catalogue but has not yet been through editorial review, so the guidance below is limited to what our structured data supports. We publish deeper diagnostic content only after a code has been reviewed — here is why.
The temperature sensor monitoring the electric brake booster (iBooster, eBooster) returns no usable signal. Without temperature feedback the controller derates booster assist to protect the motor.
A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.
- Safe to drive
- Driving may cause further damage or leave you stranded. Arrange service promptly rather than waiting.
- Urgency
- Get it looked at now
- Will it pass emissions
- Not affected
- Check engine light
- Solid
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Many vehicles show no symptom at all beyond the warning light. The absence of a symptom does not mean the fault is not real.
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | Open sensor element or broken sensor wire | Very common | — |
| 2 | Corroded connector on the booster sensor pigtail | Common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
- Electric Brake Booster
- Temperature Sensor
- Wiring Harness
- Definition
- Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
- Diagnostic guidance
- Written and reviewed in-house. See our editorial policy.
- Review status
- Awaiting review
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