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P2227







P2227-BAROMETRIC PRESSURE SENSOR RATIONALITY

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The barometric pressure sensor is used to measure exhaust gas pressure in the intake manifold. The Electronic Control Module (ECM) provides a 5-volt supply to the barometric pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The barometric pressure sensor provides a signal to the ECM on the barometric pressure sensor signal circuit. This sensor signal voltage changes based on the environmental pressure. There are two parts to this fault code, a key on check and a rationality check. At key ON, the readings for the boost pressure, exhaust gas pressure, and barometric pressure are compared. This fault code occurs if the barometric pressure reading is different from the other two. This diagnostic is run 5 seconds after key on. During normal engine operation the rationality check verifies the pressure reading is below the barometric pressure value at one mile below sea level. If the sensor 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 has to fail in two consecutive drive cycles for the MIL to become illuminated. During this time the ECM uses an estimated barometric pressure. The ECM turns off the MIL when the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
While the engine is running.

- Set Condition:
The ECM does not read a change in value from the sensor over time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. INLET TEMPERATURE/PRESSURE SENSOR
Turn the ignition on.
Wait 5 seconds after ignition is turned ON, using the scan tool, check DTCs
Is P2227 stored?

Yes


- Go to2


No


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



2. INTERMITTENT CONDITION
Erase the DTC with the scan tool.
Start the engine and let it idle for 1 minute. With the scan tool, monitor the ambient air pressure reading.
Does the value fluctuate slightly, indicating the sensor is not stuck?

Yes


- Repair complete


No


- Replace the barometric pressure sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test