Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 383 PID: S70 SPN: 729 FMI: 5/5 Engine Intake Air Heater 1 Circuit – Current Below Normal or Open Circuit

Lamp:
Amber

Reason:
A malfunctioning engine intake air heater circuit has been detected.

Effect:
Engine may not start or may be difficult to start.

Circuit Description:
The intake air heater improves starting and white smoke control in cold ambient conditions.

Component Location:
The intake air heater is located at the air inlet connection to the intake manifold. The location of the intake air heater relays will vary by vehicle and engine configuration.

Conditions for Running the Diagnostics:
This diagnostic runs at initial key ON when the intake air heater is commanded ON.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the voltage drop during intake air heater operation was less than expected.

Action Taken When the Fault Code Active:
The ECM illuminates the amber check engine lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault Code:
1. To validate the repair, perform a key cycle and leave the key in the ON position for 2 minutes. Then start the engine and let it idle for 1 minute.
2. The fault code status displayed by the diagnostic tool will change to inactive immediately after the diagnostic runs and passes.
3. The ECM will turn off the amber check engine lamp immediately after the diagnostic runs and passes.
4. For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5. The reset all faults command in the diagnostic tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
Possible causes of this fault code include:
1. A malfunctioning engine intake air heater.
2. An open circuit in the engine harness.
3. A short circuit to ground in the engine harness.