Cummins ISB6.7 CM2150 (2007-09) Fault Code: 2555 PID: SID 070 SPN: 729 FMI: 3 Intake Air Heater 1 Circuit – Voltage Above Normal or Shorted to High Source. High voltage detected at the intake air heater signal circuit.

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. Use the following procedure to calibrate the ECM, if necessary.

Possible causes:

1)Intake air heater relay signal wire not connected to the relay
2)Intake air heater relay return wire not connected to the relay
3)Open circuit in the intake air heater relay signal wire
4)Open circuit in the intake air heater relay return wire
5)Intake air heater signal wire shorted to a voltage source.

Possible repairs:

1)Replace the intake air heater relay.
2)Repair or replace the OEM harness.
3)Replace the ECM.