P0237 indicates that the powertrain control module (PCM) has detected a voltage signal from the turbocharger or supercharger boost sensor that falls below the expected range for the given operating conditions. This typically means the sensor circuit is reading less than approximately 0.5 volts, suggesting a short to ground, open circuit, or internal sensor failure. The code sets when the PCM determines the boost pressure reading is implausibly low compared to other engine parameters.
The sensor's internal circuitry has degraded or failed, causing it to output voltage below specification regardless of actual boost pressure, often due to heat cycling or moisture intrusion.
The signal wire between the sensor and PCM has chafed against the engine block, exhaust manifold, or frame, creating a path to ground that pulls the circuit voltage low.
Moisture intrusion, bent pins, or terminal spread in the sensor electrical connector creates excessive resistance or a partial short that drops the signal voltage below threshold.
Interruption in the 5-volt reference supply wire from the PCM to the sensor prevents proper sensor operation, though this typically affects multiple sensors simultaneously.
Rarely, the PCM's analog-to-digital converter or internal voltage supply has failed; this should only be considered after verifying sensor and wiring integrity, as PCM failure is statistically unlikely for this specific code.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
While the engine may still run, continued operation risks catalytic converter damage from improper air-fuel ratios and potential mechanical damage from unregulated boost; repair should be prioritized and boost-heavy driving avoided.
No, that is usually incorrect. The vast majority of P0237 faults are resolved by replacing the boost sensor or repairing wiring; PCM failure is rare and should only be suspected after exhaustive testing of the sensor and entire circuit.
Circuit low codes indicate electrical failures rather than contamination; while cleaning the sensor mounting port is good practice during replacement, cleaning alone rarely resolves a circuit voltage issue caused by internal sensor failure or wiring shorts.
P0236 indicates the sensor is reporting a value outside the expected mechanical range for current conditions, while P0237 specifically indicates the electrical circuit voltage is below the minimum threshold, usually pointing to wiring or sensor failure rather than a pressure discrepancy.