For 1990-2009 cars

### 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 Descriptors

DTC P2226 03: Barometric Pressure (BARO) Sensor Circuit Voltage Below Threshold
DTC P2226 07: Barometric Pressure (BARO) Sensor Circuit Voltage Above Threshold
DTC P2228: Barometric Pressure (BARO) Sensor Circuit Low Voltage
DTC P2229: Barometric Pressure (BARO) Sensor Circuit High Voltage

### Circuit/System Description

The BARO sensor is integrated within the engine control module (ECM). The barometric pressure (BARO) sensor responds to changes in altitude and atmospheric conditions. The BARO sensor provides the ECM an indication of barometric pressure. 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 ignition is ON or the engine is operating.

### Conditions for Setting the DTC

#### P2226 03 and P2228

• | The ECM detects that the BARO sensor voltage is less than 2.1 volts.

• | The condition exists for greater than 0.5 seconds.

#### P2226 07 and P2229

• | The ECM detects that the BARO sensor voltage is greater than 4.7 volts.

• | The condition exists for greater than 0.5 seconds.

### Action Taken When the DTC Sets

DTCs P2226, P2228, and P2229 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P2226, P2228, and P2229 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls 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

• | Scan Tool Output Controls

### Circuit/System Verification

Important: If you were sent here from P0069, proceed to Circuit System Testing.

1. Start the engine, observe the DTC information with a scan tool. DTCs P2226, P2228, or P2229 should not set.
2. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

### Circuit/System Testing

1. Inspect the atmospheric vent on the 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 P0069, P2226, P2228, or P2229 should not set.

⇒ | If DTC P0069, P2226, P2228, or P2229 sets, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming