P0236Powertrain
Powertrain · SAE
Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance
Meaning
Boost sensor A is operating and the signal is within the electrical range, but the reading does not match the expected boost pressure from the ECM model. The signal is plausible but incorrect.
Common causes
- Air leak in the boost circuit (intercooler, pipes, joints)
- MAP/boost sensor with calibration offset or drift
- Variable geometry actuator or wastegate not operating correctly
- Partial obstruction in the duct between turbo and manifold
- Abnormal wiring resistance (not enough to trigger a circuit fault)
Symptoms
- Check-engine light on
- Reduced power or abnormal turbo response
- Increased fuel consumption
- Possible turbo overboost or underboost
- Out-of-specification emissions
Severity
Moderate to high: incorrect turbo regulation compromises performance and can lead to overboost damage if not addressed.
What to do
- Compare the boost sensor value against actual pressure measured with an external gauge
- Inspect all boost circuit hoses and connections for leaks
- Check wastegate or VGT actuator operation
- Evaluate sensor calibration and replace it if drift is confirmed
- Clear the duct between turbo and manifold of any obstruction