Fuel and air

P0237 — Turbo Boost Pressure Sensor A Circuit Low

Severity: medium Drive with care, to a shop

What P0237 means

P0237 means the engine control module detected an abnormally low voltage from the turbo or supercharger boost pressure sensor A circuit. This sensor measures air pressure in the intake after the compressor, and the ECM uses it to control boost and fueling. When the signal falls below the expected range, the ECM can't manage boost accurately and usually cuts engine power.

Symptoms

  • Check Engine light on
  • Reduced power and sluggish acceleration
  • Limp mode
  • Poor fuel economy
  • Whistling or hissing from the intake or turbo
  • Hesitation under boost

Possible causes

  1. Failed boost pressure sensor A
  2. Damaged or corroded wiring or connector at the sensor
  3. Signal wire shorted to ground
  4. Open or short in the sensor's 5 V reference circuit
  5. Intake leaks or loose or split boost hoses
  6. Mechanical turbocharger fault
  7. Faulty ECM (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and look for other boost or MAP codes
  2. Inspect the sensor connector and wiring for damage, corrosion and chafing
  3. With the engine off, check the sensor reading in live data against ambient pressure
  4. Use a multimeter to test the 5 V supply, ground and signal wires
  5. Test the signal wire for a short to ground and for an open circuit
  6. Check hoses, clamps and the intercooler for leaks, and smoke or pressure test the intake if needed
  7. Compare commanded and actual boost on a road test and check turbo actuator movement
  8. Swap in a known good sensor and recheck

Common fixes

  • Replace boost pressure sensor A
  • Repair the wiring or replace the connector
  • Fix intake leaks and replace damaged hoses or clamps
  • Repair or replace the turbocharger if it is mechanically faulty
  • Replace or reprogram the ECM if confirmed faulty

Questions and answers

Can I drive with a P0237 code?

Briefly and gently, yes, but power will likely be limited. Avoid heavy loads and get it diagnosed soon.

What most often causes P0237?

Usually the boost pressure sensor itself or damaged wiring and connectors. Start with a wiring inspection and a check of the sensor's supply voltage and signal.

Will clearing the P0237 code fix the problem?

Clearing it only turns off the light for a while. If the cause remains, the code will return and the engine may go into limp mode again.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.