P2227

P2227-BAROMETRIC PRESSURE SENSOR RATIONALITY





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The barometric pressure is measured by the Inlet Air Temperature/Pressure Sensor, which is located on the Air Cleaner Assembly. There is a key on check and a rationality check. At key on, the readings for the Intake Manifold Pressure Sensor, Exhaust Gas Pressure Sensor, and Inlet Air Pressure Sensor are compared. This fault code occurs if the inlet air pressure reading is different from the other two. During normal engine operation the rationality check verifies the inlet air pressure is reading an unreasonable value for a calibrated period of time then an error is recorded. The key-on portion of the rationality will light the MIL immediately after the diagnostic runs and fails. The rationality portion is a one trip fault. During this time the Powertrain Control Module (PCM) uses an estimated barometric pressure. The PCM turns off the MIL when the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Key off.

- Set Condition:
The Powertrain Control Module (PCM) detects that the key off value differs from the other pressure sensors by a calibrated amount.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. INLET TEMPERATURE/PRESSURE SENSOR
1. Turn the ignition on.
2. Wait five seconds after ignition is turned on, using the scan tool, check DTCs.

Is P2227 Active or Stored?

Active

- Replace the Inlet Air Temperature/Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

Stored

- Go To 2

2. INTERMITTENT CONDITION
1. Erase the DTC with the scan tool.
2. Start the engine and let it idle for 1 minute. With the scan tool in sensors, monitor the Inlet Air Pressure Sensor reading.

Does the value change, indicating the sensor is not stuck?

Yes

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

No

- Replace the Inlet Air Temperature/Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.