P2227

DTC P2227, P2228, or P2229 (LLT, LY7)

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 P2227
- Barometric Pressure (BARO) Sensor Performance

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 ECM uses this information to calculate fuel delivery. 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

P2227
* Before the ECM can report DTC P2227 failed, DTCs P0100, P0101, P0102, P0103, P0121, P0122, P0123, P0221, P0222, P0223, P2228, and P2229 must run and pass.
* The engine is operating for greater than 1 s.
* The mass air flow sensor signal is valid.
* The evaporative emission (EVAP) leak test is not enabled.
* DTC P2227 runs continuously once the above conditions are met for 2 s.

P2228 or P2229
* The engine is operating.
* The DTCs run continuously once the above conditions are met for 2 s.

Conditions for Setting the DTC

P2227
* The ECM detects that the BARO pressure is less than 50 kPa or greater than 115 kPa and DTC P2228 or P2229 is not set.
* The ECM detects that the BARO pressure changed greater than 10 kPa within 20 s.
* The ECM detects that the BARO pressure changed greater than 30 kPa since the last ignition cycle, and the difference between the BARO signal and the calculated BARO is greater than 2 kPa. The condition exists within 1 s of engine start up.
* DTC P2227 sets if any of the conditions above exist for greater than 1 s.

P2228

The ECM detects that the BARO sensor voltage is less than 0.20 V for 1 s.

P2229

The ECM detects that the BARO sensor voltage is greater than 4.87 V for 1 s.

Action Taken When the DTC Sets

DTCs P2227, P2228, and P2229 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P2227, P2228, and P2229 are Type B DTCs.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

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

Circuit/System Verification

1. Start the engine. Observe the DTC information with a scan tool. DTCs P2227, P2228, or P2229 should not set.
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. Start the engine. Observe the DTC information with a scan tool. DTCs P2227, P2228, or P2229 should not set.

• If DTC P2227, 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 engine control module replacement, setup, and programming