P0237Powertrain
Powertrain · SAE
Turbocharger/Supercharger Boost Sensor A Circuit Low
Meaning
The output voltage of boost pressure sensor A is below the minimum operating range threshold. The ECM interprets the signal as a short to ground or open signal circuit.
Common causes
- Short to ground on the boost sensor signal wire
- Open 5 V reference supply line to the sensor
- Failed MAP/boost sensor with output stuck low
- Corroded or disconnected connector
- Signal wire damage along the route
Symptoms
- Check-engine light on
- Boost pressure reading at zero or below minimum
- Severe power reduction or limp-home mode
- Excessive smoke (black on diesel, incorrect substitute signal)
- Absent or minimal turbo response
Severity
High: without a turbo pressure reading the ECM applies a conservative fuelling limit; prolonged driving is not recommended.
What to do
- Measure 5 V reference supply voltage at the sensor
- Measure signal voltage: below 0.2 V indicates short to ground or failed sensor
- Check signal wire continuity from sensor to ECM
- Inspect the connector for corrosion, bent pins, or breaks
- Replace the MAP/boost sensor if the circuit is intact