Cummins ISX15 CM2250 (2010-12) Fault Code: 3733 PID: SPN: 862 FMI: 3 Crankcase Breather Filter Heater Circuit- Voltage Above Normal or Shorted to High Source

Circuit Description
The crankcase breather heater is used to keep the crankcase breather filter housing from freezing. The engine control module (ECM) supplies 12-VDC to the breather heater when heating is commanded.

Component Location
The crankcase breather heater is mounted to the crankcase breather filter housing.

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

Conditions for Setting the Fault Codes
The ECM detects that the crankcase breather heater signal voltage is greater than 1.5-VDC for more than 10 seconds.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
The crankcase breather heater will be disabled.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
Possible causes of this fault code include:

Short circuit to voltage in the crankcase breather heater circuit
Malfunctioning ECM.

Possible Cause:
1) Engine Harness
2) ECM failure