OBD Codes

P0238

Turbo/Super Charger Boost Sensor "A" Circuit High

Moderateturbo

Overview

The P0238 code indicates a turbo/super charger boost sensor "a" circuit high condition has been detected by the PCM. This code relates to the turbocharger/supercharger system that provides forced induction to increase engine power. Issues with the boost system can result in reduced power, poor fuel economy, and potential turbocharger damage if not addressed.

Symptoms

  • Black or blue smoke from exhaust
  • Oil leak near turbocharger
  • Reduced engine power
  • Poor acceleration

Common Causes

  • Failed bypass valve or blow-off valve
  • Damaged turbo oil supply or return line
  • Failed turbocharger boost pressure sensor
  • Boost leak in intercooler piping

Diagnosis Steps

  1. 1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
  2. 2Inspect all boost hoses and intercooler piping for leaks or disconnections
  3. 3Test the boost pressure sensor with a multimeter or scan tool live data
  4. 4Check the wastegate and bypass valve for proper operation
  5. 5Inspect the turbocharger for shaft play, oil leaks, or damage

Estimated Repair Cost

$200$3,000

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

BMW 335iVolkswagen GTIChevrolet Cruze TurboMini Cooper S

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Frequently Asked Questions

Minor turbo codes like sensor issues may allow careful driving, but significant boost or oil-related turbo codes should be addressed immediately to prevent turbocharger failure, which is very expensive to repair.