Technical Definition:

Turbocharger / Supercharger Underboost

Technical Description:

The DTC code refers to a condition where the PCM/ECM (powertrain/engine control module) has detected that the bank “A” or single turbocharger or supercharger is not providing a normal amount of boost.

Possible Causes:

• Intake (induction) air restriction or leak
• Failed or damaged turbocharger (sticking, binding, etc.)
• Faulty boost/charge pressure sensor
• Faulty wastegate bypass regulator valve (VW)
• Low fuel pressure condition (Isuzu)
• Sticking turbo nozzle control solenoid (Isuzu)
• Faulty injector control pressure (ICP) sensor (Ford)
• Low oil pressure (Ford)
• EGR system fault (Ford)
• Variable geometry turbocharger (VGT) actuator (Ford)
• VGT vanes sticking (Ford)

Possible Symptoms:

• MIL (Malfunction indicator lamp) illumination
• Reduced power output from engine, possibly in a limp mode
• Unusual sounds from the engine/turbo

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

Specific Makes: