CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – 019-370   EGR Differential Pressure Sensor

Disconnect the wiring harness connector.

Remove the mounting capscrews.

Remove the sensor.

Clean the exhaust gas recirculation (EGR) differential pressure sensor and adapter mounting surfaces. Remove any dirt build-up or soot residue.

Inspect the EGR differential sensor bracket for cracks or fretting. If damage is present, the sensor
must be replaced. The bracket is
not a serviceable component.

Inspect the o-rings for cracks or other damage. Replace the o-rings if cracks or other damage is found.

Install the EGR differential pressure sensor. Make sure the o-rings are captured in the bottom of the sensor.

Connect the wiring harness to the sensor.

Make sure the sensor is installed correctly. Verify that the sensor connector is facing inward toward the engine on the ISX engine. There is a locating feature or raised nub located on the sensor adapter to aid in the installation of the sensor. This raised nub is located on the outside and rearward edge of the sensor adapter. If installed correctly, the sensor will sit flat on the sensor adapter and will clear the raised nub.

On the ISM engine, the sensor connector will be facing outward away from the engine. There is a locating feature as well on the sensor adapter for the ISM engine. The locating feature is located at the inward and rearward edge of the sensor adapter. If installed correctly, the sensor will sit flat on the sensor adapter and will clear the raised nub.

Start the engine and verify proper operation (no fault codes).

NOTE: An active EGR differential pressure sensor fault code requires a certain procedure, once the repair is complete, to get the fault code to go inactive. The engine
must be started and the engine coolant temperature
must be above 68°C [154°F] and the intake manifold air temperature
must be above 7°C [45°F]. Shut the keyswitch off for 30 seconds and turn the keyswitch back on. The fault code will then transition to inactive.