Cummins ISB CM850 (2003-06) Fault Code: 1228 PID: 27 SPN: 27 FMI: 2 EGR Valve Position – Data erratic, intermittent, or incorrect. Intermittent EGR position information is being received by the electronic control module (ECM).
This fault code is caused by an internal failure of the EGR valve position sensor. This failure causes erratic readings of EGR valve position.
Possible repairs:
1)Replace the EGR position sensor.