P0237: Turbocharger/Supercharger Boost Sensor A Circuit Low. Meaning, possible symptoms and checks before repair.
Meaning, symptoms, causes and checks
The controller detects an excessively low electrical input from boost pressure sensor A. This does not automatically prove insufficient boost or a failed turbocharger. Identify the letter and sensor location from engine-specific information.
Affected system: Powertrain
Symptoms
- Reduced power and slow acceleration; boost may be limited.
- Engine warning light; sometimes the issue is apparent only in diagnostic data.
Possible causes
- Signal shorted to ground, missing reference or poor terminals.
- Failed pressure sensor; confirm the electrical fault before testing the turbocharger.
What to check
- Identify sensor A and read related MAP/BARO or supply codes; note whether faults occur at key-on or under load.
- With the engine stopped and pressures equalized, compare its reading with atmospheric pressure and relevant sensors using OEM criteria.
- Measure reference, ground and signal; check for shorts to ground, opens and other loads sharing the reference.
- Compare voltage at the sensor and module; a low scan-tool pressure may merely be the conversion of a faulty input.
- After repair, clear codes and recheck sensor A and comparison pressures under the original recorded conditions, following the manufacturer’s procedure.
Also written as: P0237-00, P023700, PO237 (some scan tools add the fault-type byte, e.g. -00).