P2227

DTC P2227

CIRCUIT 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 action into electrical resistance. The BARO sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The BARO sensor provides a signal voltage to the ECM, relative to the pressure changes on the BARO sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

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 105 kPa at or below sea level. The BARO sensor has a range of 8-207 kPa. The ECM uses the BARO sensor input for fuel delivery and other diagnostics.

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, DTC P2227 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P2227 Barometric Pressure (BARO) Sensor Performance

CONDITIONS FOR RUNNING THE DTC
- DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0237, P0238, P0299, P0335, P0336, P0500, P2228, and P2229 are not set.
- The engine speed is between 580-900 RPM.
- The engine run time is more than 8 seconds.
- The vehicle speed is less than 40 km/h (25 mph).
- The accelerator pedal position (APP) is less than 69 percent.
- The engine coolant temperature is more than 20°C (68°F).
- The mass air flow (MAF) is less than 50 g/s.
- The power take-off (PTO) is not active.
- The above conditions are met for 5 seconds.
- DTC P2227 runs continuously once the above conditions are met.
- DTC P2227 runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ECM detects that the difference between the BARO pressure and the boost pressure is more than 15 kPa for 6 seconds.

ACTION TAKEN WHEN THE DTC SETS - FEDERAL
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center (DIC), if equipped, may display a message.

ACTION TAKEN WHEN THE DTC SETS - CALIFORNIA
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that 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.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-9:

Steps 10-21:

Steps 22-28:

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the ability of the boost pressure sensor to correctly indicate barometric pressure.
8. This step tests the circuits and the controller output.
14. This step tests the circuits and the controller output.