Cummins ISB CM850 (2003-06) Fault Code: 2555 PID: SID 70 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. Possible causes: 1)Intake air heater relay signal wire not connected to the relay2)Intake air heater relay return wire not connected to the relay3)Open circuit in the intake air heater relay signal wire4)Open circuit in the intake air heater relay return wire5)Intake air heater signal wire shorted to a voltage source. Possible repairs: 1)Flush the dirt, debris, or moisture from the connector pins.2)Install...

Cummins ISB CM850 (2003-06) Fault Code: 2556 PID: SID 70 SPN: 729 FMI: 4 Intake Air Heater #1 Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at the intake air heater signal circuit. Possible causes: 1)A shorted intake air heater relay2)Intake air heater relay supply wire shorted to ground. Possible repairs: 1)Replace the damaged intake air heater relay.2)Repair or replace the OEM harness.3)The removal and installation of the connector may correct the fault.4)Replace the ECM. Cummins ISB CM850 (2003-06) Fault Code: 2555 PID: SID 70 SPN: 729 FMI: 3 Intake Air Heater #1 Circuit –...

Cummins ISB CM850 (2003-06) Fault Code: 2557 PID: SID 57 SPN: 697 FMI: 3 Auxiliary PWM Driver #1 – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the analog torque circuit. The default setting for Transmission PWM output Type in INSITE? electronic service tool is 805. The PWM output only has meaning with non-electronic Allison Transmission? AT545. Older software and ECMs had no diagnostics on this output and having the default set at 860 was of no consequence. Newer software and ECMs do have a diagnostic if this output is selected but no hardware is...

Cummins ISB CM850 (2003-06) Fault Code: 2558 PID: SID 57 SPN: 697 FMI: 4 Auxiliary PWM Driver #1 – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the analog torque circuit. Possible causes: 1)A faulty transmission shift modulator2)An short circuit to ground on the output device driver line3)A short pin to pin in the output device driver line. Possible repairs: 1)Replace the transmission shift modulator.2)Repair or replace the OEM harness.3)The removal and installation of the connector may correct the fault.4)Replace the ECM. Cummins ISB CM850 (2003-06) Fault Code: 2557 PID: SID 57 SPN: 697 FMI:...

Cummins ISB CM850 (2003-06) Fault Code: 2559 PID: SPN: 1845 FMI: 4 Transmission ECU to ECM Communication Lost – Abnormal Update Rate. No communication or an invalid data transfer rate has been detected between the ECM and the transmission ECU. When this fault code is active, some multiplexed devices may not function as desired. Possible causes: 1)When the ECM is set up properly (components enabled and OEM VECU source addressed correctly) to receive information from an OEM VECU, but the OEM VECU is actually transmitting a message that says that component is not available for multiplexing. This can be caused...