Cummins ISL CM850 (2003-06) Fault Code: 957 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. The troubleshooting information for fault code 957 is the same as fault code 1228. Refer to fault code 1228 for the fault code troubleshooting information.
Possible repairs:
1)Replace the EGR position sensor.