SPN 3703: regen blocked by switch
Regens are blocked because the inhibit switch is on. Type another SPN and FMI to check it.
Regens are blocked because the inhibit switch is on.
- Turn the regen inhibit switch off.
- Watch the soot load; it will keep climbing until a regen runs.
Paste the whole line if you like: "SPN 3251 FMI 0", "3251/0" or Deere's "003251.00". Plain-words guidance; the service manual wins.
What SPN 3703 means
Regens are blocked because the inhibit switch is on.
How urgent it is
Schedule it. Put it on the next service. Watch for it to come back.
What to check first
- Turn the regen inhibit switch off.
- Watch the soot load; it will keep climbing until a regen runs.
Plain-words guidance for a foreman, not a repair procedure. Makers add their own codes and steps; the machine's service manual wins.
Next time, Dozer catches the code when it fires.
Plug a CAN logger into the machine's J1939 port, or connect the telematics you have. When a code fires, Dozer opens a repair ticket with the meaning, how urgent it is and what to check.
- The code, the machine and its hours on one ticket
- Severity sorted: keep working, plan a stop, or stop now
- The mechanic gets the checklist before they drive out
- Repeat codes on the same machine get flagged
LIVE EX-04 · SPN 3251 FMI 0 · plan a stop today Photo is an AI-generated stand-in, not a customer site.
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Questions crews ask
What does SPN 3703 mean?
Regens are blocked because the inhibit switch is on.
Can I keep running with SPN 3703?
Schedule it. It can wait for a planned stop, but don't let it ride for weeks. If the machine derates or the stop lamp is on, stop.
What should I check first for SPN 3703?
Turn the regen inhibit switch off. Watch the soot load; it will keep climbing until a regen runs.
How do I clear SPN 3703?
Fix the cause first. Most codes go inactive by themselves once the condition is gone and the engine has run a key cycle or two. Clearing it with a service tool without a fix only hides it until it comes back.
Which machines show SPN 3703?
Any diesel that speaks SAE J1939: excavators, dozers, loaders, haul trucks, generators and on-road trucks with Cat, Cummins, Deere, Komatsu, Volvo, Kubota, Perkins and other engines. The SPN means the same thing on all of them; the fix steps can differ, so check the service manual.
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