Error code

OBD2 P0238

OBD2P0238
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Turbo/Super Charger Boost Sensor 'A' Circuit High.

Severity

severeCan drive, but with significant power loss and risk of engine damage.

Summary

P0238 indicates that the Manifold Absolute Pressure (MAP) sensor A in the turbocharger system is reporting an abnormally high signal voltage to the PCM.

Symptoms

  • Stored trouble code and illuminated warning light
  • Severe loss of engine power
  • Vehicle enters fail-safe or limp mode
  • Non-metal parts of inlet ducting may burst under excessive boost pressure
  • Turbocharger may emit unusual sounds like whistling, knocking, grinding, or hissing
  • Engine misfires or detonation on all cylinders (indicated by knock sensor or misfire codes)
  • Spark plug fouling and excessive smoke from the tailpipe

Common Causes

  • Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
  • Defective MAP or boost control sensor
  • Mechanical failure of the waste gate mechanism
  • Failed vacuum actuator or check valve if system is vacuum operated
  • Clogged catalytic converters or mufflers preventing free flow of exhaust gas

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Inspect wiring for damage or corrosion.
  3. Check vacuum lines and actuators if system is vacuum operated.
  4. Verify actual boost pressure using a gauge.
  5. Perform electrical tests on MAP sensor and related circuits.

Fixes

  • Replace defective MAP/boost control sensor
  • Repair or replace damaged wiring/connectors

FAQ

What does P0238 mean?

P0238 indicates an abnormally high signal voltage from the MAP sensor in the turbocharger system.

How do I fix P0238?

Fixes include replacing a defective MAP/boost control sensor or repairing damaged wiring/connectors.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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