VIN L

DTC P2228 or P2229

Diagnostic Instructions

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

DTC Descriptors
DTC P2228
- Barometric Pressure (BARO) Sensor Circuit Low Voltage

DTC P2229
- Barometric Pressure (BARO) Sensor Circuit High Voltage

Circuit/System Description

The Barometric pressure (BARO) sensor responds to changes in altitude and atmospheric conditions. This gives the Engine Control Module (ECM) an indication of barometric pressure. The BARO sensor is located within the controller and is not serviced as a separate unit. The BARO sensor provides a voltage signal to the ECM relative to the atmospheric pressure changes. The ECM monitors the BARO sensor signal for a voltage outside of the normal range.

Conditions for Running the DTC

* The engine is running for greater than 10 s.
* DTC P2228 and P2229 run continuously when the above conditions are met.

Conditions for Setting the DTC

P2228

The ECM detects that the BARO sensor voltage is less than 1.97 V for 1 s.

P2229

The ECM detects that the BARO sensor voltage is greater than 4.8 V for 1 s.

Actions Taken When the DTC Sets

* DTCs P2228 and P2229 are Type A DTCs.
* The driver information center, if equipped, may display Reduced Engine Power message.

Conditions for Clearing the MIL/DTC

DTCs P2228 and P2229 are Type A DTCs.

Reference Information
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool BARO parameter and compare the value to the Altitude Versus Barometric Pressure (Altitude Versus Barometric Pressure) table. The parameter should be within the range specified in the table for the current altitude.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Inspect the atmospheric vent on the K20 ECM case for one of the following conditions:

* Moisture in the vent inlet
* Debris in the vent inlet

• If a condition exists, attempt to clean or dry the atmospheric inlet.

2. Engine running, observe the DTC information with a scan tool. DTC P2228 or P2229 should not set.

• If DTC P2228 or P2229 sets, replace the K20 ECM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for ECM replacement, setup, and programming