P2228

DTC P2228

CIRCUIT DESCRIPTION
The barometric pressure (BARO) sensor is installed inside of the engine control module (ECM) and converts the BARO into a voltage signal. The ECM uses this voltage signal to calibrate the fuel injection quantity and injection timing for altitude compensation. If the ECM detects an excessively low BARO signal voltage, this DTC will set.

Condition for Running the DTC
- DTC P2229 is not set.
- The battery voltage is more than 7 volts.
- The ignition switch is ON.
- The engine is running.

Condition for Setting the DTC
- The ECM detects that the BARO sensor signal voltage is less than 1.5 volts for longer than 1 second.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) 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.
- The ECM uses a BARO substitution of 14.7 psi (101.3 kPa) when the DTC is set.
- The ECM uses a BARO substitution of 10.5 psi (72.4 kPa) for engine starting and running.
- The ECM limits fuel injection quantity within 70%.
- The ECM closes the EGR valve and holds to close position.

Condition for Clearing the MIL/DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail. (12,000 lbs GVW)
- The ECM turns OFF the MIL when the diagnostic runs and does not fail. (Except 12,000 lbs GVW)
- 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.

DTC P2228