GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2227: Barometric Pressure (BARO) Sensor Performance

Circuit/System Description

The barometric pressure (BARO) sensor is installed inside of the engine control module (ECM) and converts the BARO into a voltage signal. The ECM uses this voltage signal to calibrate the fuel injection quantity and injection timing for altitude compensation. Within the ECM, the diagnostic compares the BARO sensor input to the boost pressure sensor input.

Conditions for Running the DTC

    • DTCs P0079, P0080, P0102, P0103, P0117, P0118, P0126, P0237, P0238, P02E8, P02E9, P0500, P0506, P0507, P0602, P0642, P0643, P1125 and P268A are not set.
    • The following conditions are met for longer than 3 seconds:
       - The battery voltage is between 10-16 volts.
       - The ignition switch is ON for longer than 2 seconds.
       - The engine speed is between 500-800 RPM.
       - The vehicle speed is less than 2 mph.
       - The engine coolant temperature is more than 20°C (68°F).
       - The engine run time is longer than 30 seconds.
       -  The accelerator pedal position is less than 2 percent.
       -  The MAF volume is between 800-1600 mg/cyl.
       - The exhaust brake switch is OFF.
    • The following conditions are met for longer than 10 seconds:
       - The intake throttle position is less than 55 percent.
       - The DPF status is Not during regeneration.
       - The exhaust brake control is commanded OFF.
       - The VNT control mode is Normal.
       -  The differential pressure is between -10 and +20 kPa
       -  The above conditions are met for 3 seconds.

Conditions for Setting the DTC

The ECM detects that the difference between the BARO pressure and the boost pressure is more than 7.5 kPa for longer than 5 seconds.

Action Taken When the DTC Sets

DTC P2227 is a Type B DTC.

Conditions for Clearing the DTC

DTC P2227 is a Type B DTC.

Diagnostic Aids

An incorrectly installed turbocharger boost sensor will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Controls Component Views
    •  Engine Control Module Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

Important: 

   • If DTCs P0079, P0080, P0102, P0103, P0117, P0118, P0126, P0237, P0238, P02E8, P02E9, P0500, P0506, P0507, P0602, P0642, P0643, P1125 and P268A are not set, test and repair those DTCs first.
   • Perform Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Test the voltage and ground circuits to the ECM for a short, an open, or high resistance.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the BARO parameter with a scan tool.
  4. Compare the BARO parameter to the range specified in the altitude vs. barometric pressure table. Refer to Altitude Versus Barometric Pressure .
  5. If the BARO parameter is outside the range specified, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming