P2227
DTC P2227
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 Descriptor
DTC P2227
- Barometric Pressure (BARO) Sensor Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this diaphragm action into the voltage signal input that is used by the engine control module (ECM) for diagnostics, emissions control, and to calculate fuel delivery.
Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4 267 meters (14,000 feet), to 104 kPa at or below sea level. The BARO sensor has a 5V reference circuit, a low reference circuit and a signal circuit. The BARO sensor provides a voltage signal to the ECM on a signal circuit relative to barometric pressure changes.
Conditions for Running the DTC
* DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0220, P0502, P0503, P2135, P2228, P2229 are not set.
* The engine run time is greater than 10 seconds.
Conditions for Setting the DTC
The ECM detects that 80 out of 100 consecutive BARO sensor samples vary greater than 10 kPa between each sample, for 10 seconds.
Action Taken When the DTC Sets
DTC P2227 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2227 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (LS3) ([1][2]Electrical Diagrams)Engine Controls Schematics (LS7) ([1][2]Electrical Diagrams)Engine Controls Schematics (LS9) ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
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
Special Tools
J 35555 - Metal Mityvac
Circuit/System Verification
1. Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO sensor parameters. The readings should be within 5 kPa of each other and also the current BARO for your location. Refer to Altitude Versus Barometric Pressure (Altitude Versus Barometric Pressure).
2. Operate the vehicle within the Conditions for Running the DTC to verify that 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
Engine running, monitor the BARO parameter with the scan tool for a steady value.
If the BARO parameter is not a steady value, test the BARO circuit for an intermittent short or open. If all circuits test normal, replace the BARO sensor.
Component Testing
Note: You must perform the Circuit/System Testing before proceeding with the Component Test.
1. Ignition ON, engine OFF, remove the BARO sensor.
2. Install a 3A fused jumper wire between the 5V reference terminal 1 of the sensor and 5V reference.
3. Install a jumper wire between the low reference terminal 2 of the sensor and ground.
4. Install a jumper wire at the signal terminal 3 of the BARO sensor.
5. Connect a DMM between the jumper wire from terminal 3 of the sensor and ground.
6. Install the J 35555 - Metal Mityvac to the BARO sensor vacuum port. Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 5.2-0V, without any spikes or dropouts.
• If the voltage is not within the specified range or is erratic, replace the BARO sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Barometric Pressure Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming