Cummins fault code 2662
At Least One Unacknowledged Moderately Severe Fault: condition exists
What it means
Cummins' description: At Least One Unacknowledged Moderately Severe Fault - Condition Exists.
SPN 629 is Controller #1. FMI 31 means the ECM has confirmed the condition described in the code is happening.
The engine ECM talks to the transmission, ABS, dash and aftertreatment modules over the J1939 data network. These codes mean the ECM itself, its calibration, or its communication with other modules has a problem.
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 network timeout logged once, often during cranking, that cleared.
Schedule a repair
Gauges dropping out, the transmission or ABS acting odd, or codes returning. Book diagnosis. These can go from annoying to stranded quickly.
Stop and get help
Red lamp for an ECM internal failure, or the engine won't start or shuts down. Get it towed or seen where it sits.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- ECM calibration doesn't match the vehicle or another module
- ECM internal failure
What you can check before calling
- Note which other systems acted up: gauges, transmission, ABS
- Check for recent electrical work or aftermarket devices plugged into the diagnostic port
- Check batteries and grounds
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
Engines and sources
Listed by Cummins for: QSX 15. 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: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.
Same SPN, other failure types
- 111 SPN 629 FMI 12
ECM Critical Internal Failure: bad device or component - 343 SPN 629 FMI 12
ECM Warning Internal Hardware Failure: bad device or component - 375 SPN 629 FMI 2
Fuel Pump Control Module, Electronic Calibration Code Error: erratic or intermittent signal - 2661 SPN 629 FMI 31
At Least One Unacknowledged Most Severe Fault: condition exists
Related ECM, network and data link codes
- 3213 SPN 1623 FMI 19
Tachograph Output Shaft Speed: network data error - 3298 SPN 1194 FMI 13
Anti-theft Encryption Seed: out of calibration - 3329 SPN 1231 FMI 2
J1939 Network #2: erratic or intermittent signal - 3331 SPN 1235 FMI 2
J1939 Network #3: erratic or intermittent signal - 3368 SPN 4490 FMI 19
Specific Humidity Sensor: network data error - 3371 SPN 1172 FMI 19
Turbocharger 1 Compressor Intake Temperature Sensor: network data error
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 2662 mean?
Cummins fault code 2662 is J1939 SPN 629 FMI 31: At Least One Unacknowledged Moderately Severe Fault - Condition Exists. In plain terms: at least one unacknowledged moderately severe fault: condition exists.
Can I keep driving with Cummins code 2662?
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 2662?
SPN 629 identifies the part or system (Controller #1). FMI 31 describes the type of failure: condition exists.
What usually causes Cummins code 2662?
The most common causes are: eCM calibration doesn't match the vehicle or another module; eCM internal failure.
Diesel down in the Midlands?
We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.