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DTC codes / P02xx · Fuel and air metering (injector circuits) / P0237

P0237Turbocharger Boost Sensor A Circuit Low

P0237 indicates that the powertrain control module has detected a low voltage signal on the turbocharger boost sensor A circuit, which typically means the sensor is reporting a boost pressure that is lower than expected or the circuit has an electrical fault. The computer sets this code when the signal voltage falls below a calibrated threshold for a set period, often indicating a short to ground, an open circuit, or a failed sensor.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Reduced engine power or limp mode due to the computer limiting boost
  • Poor acceleration and sluggish throttle response
  • Decreased fuel economy because the engine may run rich or overboost
  • Rough idle or stalling in some cases if the sensor signal is erratic
  • Black smoke from the exhaust if the engine over-fuels due to incorrect boost readings

Common causes, most likely first

  1. Faulty turbocharger boost sensor (manifold absolute pressure sensor) giving a low voltage output
  2. Damaged or corroded wiring harness or connector at the boost sensor
  3. Open circuit or high resistance in the signal wire between the sensor and the PCM
  4. Short to ground in the sensor signal circuit
  5. Poor ground connection for the boost sensor
  6. Leaks or blockages in the boost pressure sensing tube or port
  7. Rarely, a failed powertrain control module (PCM)

How to diagnose and fix it

  1. Inspect the boost sensor and its connector for physical damage, corrosion, or loose pins, and clean or repair as needed
  2. Check the sensor's reference voltage and ground circuits with a multimeter to ensure they are within specification
  3. Backprobe the signal wire at the sensor and compare the voltage reading with the expected value for the current boost level; a low reading confirms a sensor or circuit fault
  4. Perform a wiggle test on the wiring harness while monitoring the signal voltage to detect intermittent opens or shorts
  5. Check for boost pressure leaks or blockages in the sensing tube and intake system that could cause a low signal
  6. If the circuit tests good, replace the boost sensor with a known-good unit and clear the code
  7. If the code persists after sensor replacement, diagnose the PCM and its connections as the final step

Boost sensor circuit checks that save time

  • A low voltage code often results from a poor ground connection rather than a failed sensor, so always verify ground integrity before condemning the sensor.
  • The boost sensor may share its reference voltage or ground with other sensors, so a fault in a shared circuit can set P0237 along with codes for other sensors.
  • On some vehicles, a dirty or clogged boost pressure sensor port can cause a low signal without any electrical fault, so inspect the sensing passage for carbon buildup.
  • P0237 can be set by a momentary glitch during hard acceleration if the signal wire rubs against a metal component, so a thorough wiggle test is essential.
  • Replacing the sensor without checking the wiring harness is a common misdiagnosis; always perform circuit tests before parts replacement.

Can I keep driving with P0237?

It is generally safe to drive with P0237, but the vehicle may enter limp mode or exhibit reduced performance, so avoid heavy acceleration and towing until the fault is repaired. Prolonged driving with a faulty boost sensor can lead to poor fuel economy and potential engine damage from incorrect boost control, so schedule a diagnosis soon.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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