What it means
The Turbocharger/Supercharger Boost Sensor C circuit signal is below the expected threshold. This indicates a low circuit condition but does not prove the sensor is shorted.
At a glance
- Usually lights the check-engine light
How it works
This code concerns the signal circuit for turbocharger or supercharger boost sensor C. The module sees a signal below its expected threshold, which can be caused by a sensor fault, a signal wire shorted to ground, or poor contact at the connector.
Common causes
Most likely first.
- Internal short in the sensor element
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
How to diagnose it
- Record freeze-frame data and check live data for boost sensor C to confirm whether its signal is low all the time or only under particular conditions.
- Inspect sensor C's connector pins for corrosion, poor contact, or moisture, and check the harness for a signal wire rubbed through against ground.
- Check the sensing port or hose, if fitted, for blockage or damage that could make the reading inconsistent with actual boost.
- Test sensor C power, ground, and signal circuits for shorts to ground and verify connections using the wiring diagram and manufacturer's specification.
- If the wiring and connections pass, test boost sensor C itself and replace it only if it fails the specified test.
Common fixes
- Clean and secure corroded or loose sensor C connector terminals.
- Repair a signal wire shorted to ground or otherwise damaged.
- Clear a blocked sensor C port or repair a damaged sensing hose, if fitted.
- Replace boost sensor C if its output remains below specification with sound wiring.
Can I keep driving?
A low sensor C signal may cause reduced power or unpredictable boost, so avoid hard acceleration and overtaking where power is needed. Stop if the engine smokes heavily, makes a new intake noise, or loses power sharply.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.