CM2150 Electronic Control System – FAULT CODE 222

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Overview

ISB with CM2150 – Barometric Pressure Sensor Circuit SMALL | MEDIUM | LARGE

ISC and ISL with CM2150 – Barometric Pressure Sensor Circuit SMALL | MEDIUM | LARGE

Circuit Description

The electronic control module (ECM) provides a 5 volt supply to the ambient air pressure sensor on the sensor supply 1 circuit. The ECM also provides a ground on the sensor return circuit. The ambient air pressure sensor provides a signal to the ECM on the ambient air pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure of the atmosphere. The ECM will detect a low signal voltage when the vehicle is operating at high altitudes. The ECM will detect a high signal voltage when the vehicle is operating at sea level.

Component Location

The barometric pressure sensor is mounted on the main branch of the engine harness near the ECM.Refer to Procedure 100-002 (Engine Diagrams) in Section F for a detailed component location view.

Conditions for Running the Diagnostics

This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes

The ECM detects that the ambient air pressure signal voltage is less than 0.25-VDC for more than 16 seconds.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• A default value of the ambient pressure reading is used.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

Shop Talk

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

The barometric pressure sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting Fault Code 222, check for multiple faults.

Possible causes of this fault code include:

• Signal circuit open or shorted to ground in the engine harness or sensor
• Supply line open or shorted to ground.

Refer to Troubleshooting Fault Code t05-222