California (With RPO Code YF5, NE1, and VCL)

DTC P2227 (CALIFORNIA WITH RPO CODE YF5, NE1, AND VCL)

CIRCUIT DESCRIPTION
The barometric pressure (BARO) sensor responds to changes in altitude and atmospheric conditions. This gives the engine control module (ECM) an indication of barometric pressure. The ECM uses this information to calculate fuel delivery. The BARO sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The ECM supplies 5 volts to the BARO sensor on a 5-volt reference circuit, and provides a ground on a low reference circuit. The BARO sensor provides a voltage signal to the ECM on a signal circuit relative to the pressure changes. The ECM compares the BARO sensor to the exhaust gas recirculation (EGR) vacuum sensor in order to monitor the BARO sensor operation. If the difference between the two sensors is more than a predetermined amount, DTC P2227 sets.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0236, P0237, P0238, P0335, P0336, P0404, P0405, P0406, P0500, P2228, P2229 is not set.
- The engine speed is between 500-3600 RPM.
- The engine run time is more than 8 seconds.
- The vehicle speed is less than 161 km/h (100 mph).
- The mass air flow (MAF) is less than 444 g/s.
- The engine coolant temperature (ECT) is more than 20°C (68°F).
- The exhaust gas recirculation (EGR) system is not active.
- The power take off (PTO) is OFF.
- The above conditions exist for 5 seconds.

CONDITIONS FOR SETTING THE DTC
The difference between the BARO sensor and the EGR vacuum sensor is more than 10 kPa for 6 seconds.

ACTION TAKEN WHEN THE DTC SETS
- 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 1-3:

Steps 4-5:

Steps 6-7:

Steps 8-11:

Steps 12-14:

Steps 15-18:

Steps 19-22:

Steps 23-27:

Steps 28-33:

Steps 34-38:

The numbers below refer to the step numbers on the diagnostic table.
4. This step tests the ability of the BARO sensor to correctly indicate barometric pressure-The value shown for the BARO sensor varies with altitude and weather conditions.
7. This step disables the EGR system in order to determine if the EGR vacuum sensor is receiving vacuum unnecessarily.
8. This step tests for a sensor that is stuck in range.