P2227

DTC P2227

CIRCUIT DESCRIPTION
The barometric pressure (BARO) sensor is installed inside of the engine control module (ECM) and converts the barometric pressure (BARO) into a voltage signal. The ECM uses this voltage signal to calibrate the fuel injection quantity and injection timing for altitude compensation. Within the ECM, the diagnostic compares the BARO sensor input to the boost pressure sensor input. If the ECM detects that the inputs are not within a specified amount of each other, this DTC will set.

Condition for Running the DTC
- DTCs P0116, P0117, P0118, P0237, P0238, P0478, P0500, P0506, P0507, P0602, P1125 are not set.
- The ignition switch is ON.
- The engine run time is longer than 30 seconds.
- The engine speed is between 650-1050 RPM.
- The mass air flow (MAF) is less than 1600 mg/cyl.
- The engine coolant temperature (ECT) is more than 68 °F (20 °C).
- The accelerator pedal position (APP) is less than 2%.
- The vehicle speed is less than 2 MPH(3 km/h).
- Above conditions are met for 3 seconds.

Condition for Setting the DTC
- The ECM detects that the difference between the BARO pressure and the boost pressure is more than 1.1 psi (7.5 kPa) for longer than 5 seconds.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive driving cycle when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Freeze Frame/Failure Records on the second consecutive driving cycle when the diagnostic runs and fails.

Condition for Clearing the DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
- High resistance in the boost pressure sensor 5 volts reference circuit, signal circuit or low reference circuit may set this DTC.
- Use the Altitude vs Barometric Pressure table to test the boost pressure sensor and BARO sensor to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. Refer to Altitude vs Barometric Pressure.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. A skewed boost pressure sensor value (shifted to a higher pressure or lower pressure) can set this DTC. The Boost Pressure on the scan tool should read near surrounding barometric pressure with the key ON and engine OFF.
5. A skewed barometric pressure (BARO) sensor value (shifted to a lower pressure or higher pressure) can set this DTC. The BARO on the scan tool should read near surrounding barometric pressure.

DTC P2227
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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