Cummins ISB4.5 CM2150 Fault Code: 1228 PID: 27 SPN: 27 FMI: 2 EGR Valve Position – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The engine control module (ECM) uses the exhaust gas recirculation (EGR) valve position sensor to determine whether or not the EGR valve is meeting the commanded position. The ECM supplies 5 volts to the EGR valve position signal circuit, and the EGR valve position sensor outputs a voltage signal to the ECM, based on the valve position. The ECM converts this signal into a percentage value, 0 to 100, indicating the valve position. A fully open valve is equivalent to 100 percent.

Component Location
The EGR valve position sensor is internal to the EGR valve assembly and can not be serviced separately.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is operating.

Conditions for Setting the Fault Codes
The ECM detects that the EGR valve position sensor is reporting an erratic value, or the EGR valve position is not changing with engine operating conditions.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
-The EGR valve operation will be disabled, and the EGR valve will try to close.

Conditions for Clearing the Fault Code
-To validate the repair, perform a key cycle, and leave the key in the on position for 1 minute. The EGR valve will perform an auto-zero immediately after key ON.
-The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
-The ECM will turn off the MIL after 3 consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Possible Causes
-Intermittent open or short in the wiring harness
-Malfunctioning EGR valve position sensor
-Malfunctioning ECM
-Sticky or broken EGR valve.

NOTE: Do not supply 12 VDC to the EGR valve position sensor, or short the EGR valve motor wires to the EGR valve position sensor. The EGR valve position sensor is rated at 5-VDC, and sensor damage may occur.