P2228

DTC P2228

DESCRIPTION
The DTC P2228 Barometric Pressure (BARO) Sensor Circuit diagnostic monitors the BARO sensor output. The barometric pressure (BARO) sensor and circuitry are located inside of the powertrain control module (PCM). The PCM uses the barometric pressure information in order to compensate for altitude changes. The BARO sensor reading is displayed on a scan tool when the ignition switch is ON and the engine is OFF.

DTC DESCRIPTOR
This diagnostic supports the following DTC. DTC P2228 Barometric Pressure (BARO) Sensor Circuit Low Voltage.

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON.
- DTC P2228 runs continuously once the above conditions are met

CONDITIONS FOR SETTING THE DTC
The BARO is less than 1.58 volts for at least 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL).
- The PCM records the operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.
- The PCM enters the Fail Safe Function and uses default BARO values.

CONDITIONS FOR CLEARING THE MIL/DTC
- The MIL turns OFF after 3 consecutively passing trips without a fault present.
- A history DTC clears after 40 consecutive warm-up cycles without a fault.
- Perform the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
The barometric pressure varies depending on the weather conditions and the altitude. Typical barometric pressure at sea level is 100 kPa (29-30 in Hg).

If DTC P2228 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was first set.

TEST DESCRIPTION

Steps 1-6:

The numbers below refer to the step numbers in the diagnostic table.
1. The Diagnostic System Check-Computers and Control Systems prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step determines if a fault is present.
3. This step checks for a short to ground in the PCM 5-volt reference circuit. The BARO sensor shares the 5-volt reference supply from the PCM with the MAP sensor, the TP sensor, and the fuel tank pressure sensor. A short in any branch of the reference voltage circuit will cause a DTC P2228 to set.
4. After replacing the PCM a new minimum throttle position and idle speed must also be established.