Cummins fault code 384
Start Assist Device Control Circuit Error (Ether Injection): root cause not known
What it means
Cummins' description: Start Assist Device Control Circuit Error (Ether Injection).
SPN 626 is Start Assist Device Control Circuit Error (Ether Injection). FMI 11 means the ECM detected a fault in this system but can't pin down the exact type. Further testing is needed.
Cummins engines use an intake air heater (grid heater) or glow plugs to help cold starts and cut white smoke. The ECM controls the heater relay and the wait-to-start lamp.
What the lamp means
An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.
Green, yellow, red: three ways this can look
The same code can be a quick fix or a reason to shut down. Match your situation to the closest example.
Keep an eye on it
A heater code in mild weather with easy starts.
Schedule a repair
Hard starting and white smoke on cold mornings. Fix it before the cold sets in.
Stop and get help
Heater relay stuck on, batteries draining, or burning or melted cables. Disconnect and get it fixed. It's a fire and no-start risk.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Weak batteries can't power the heater
- Heater relay stuck on (can drain batteries)
What you can check before calling
- Check whether the wait-to-start lamp comes on in cold weather
- Look for burned or loose heater cable connections
- Notice hard starts and white smoke only when cold
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
Engines and sources
Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Diagnostic Fault Codes for Cummins Engines. Always confirm with Cummins service information (QuickServe) for your engine serial number.
Same SPN, other failure types
- 381 SPN 626 FMI 11
Intake Air Heater (Relay Enable) #1 Circuit: root cause not known - 382 SPN 626 FMI 11
Intake Air Heater (Relay Enable) #2 Circuit: root cause not known - 487 SPN 626 FMI 18
Start Enable Device 1 Canister Empty (Ether Injection): reading below normal (moderately severe) - 2738 SPN 626 FMI 3
Start Enable Device 1 Circuit (Ether Injection): circuit voltage high / shorted high - 2739 SPN 626 FMI 4
Start Enable Device 1Circuit (Ether Injection): circuit voltage low / shorted low
Related Intake air heater and cold start codes
- 2555 SPN 729 FMI 3
Engine Intake Air Heater 1 Circuit: circuit voltage high / shorted high - 2556 SPN 729 FMI 4
Engine Intake Air Heater 1 Circuit: circuit voltage low / shorted low - 3222 SPN 520435 FMI 12
Glow Plug Module: bad device or component - 3494 SPN 1081 FMI 7
Engine Wait to Start Lamp: not responding / out of adjustment - 3555 SPN 1081 FMI 9
Engine Wait to Start Lamp: abnormal update rate - 4252 SPN 1081 FMI 31
Engine Wait to Start Lamp: condition exists
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does Cummins fault code 384 mean?
Cummins fault code 384 is J1939 SPN 626 FMI 11: Start Assist Device Control Circuit Error (Ether Injection). In plain terms: start assist device control circuit error (ether injection): root cause not known.
Can I keep driving with Cummins code 384?
Usually for a short time, if the engine runs normally and no other warnings are on. Get it diagnosed soon, because many amber codes lead to a derate if ignored. Look at the green, yellow and red examples on this page to judge your situation.
What is the SPN and FMI for Cummins code 384?
SPN 626 identifies the part or system (Start Assist Device Control Circuit Error (Ether Injection)). FMI 11 describes the type of failure: root cause not known.
What usually causes Cummins code 384?
The most common causes are: weak batteries can't power the heater; heater relay stuck on (can drain batteries).
Diesel down in the Midlands?
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