Safe to driveTo the nearest safe stop
J1939 code SPN 1709. Below — how the fault is worded at the factory by International, and what the second half of the code (FMI) means in the standard.
| FMI 5 | Transmission Controller Power Relay — PRNDL Pseudo ignition relay driver output Under Current Or Open Circuit |
| FMI 6 | Transmission Controller Power Relay — PRNDL Pseudo ignition relay driver output overcurrent |
| SPN 1709 FMI 51709/5 · 1709.5 | current below normal or open circuit |
| SPN 1709 FMI 61709/6 · 1709.6 | current above normal or grounded circuit |
Safe to drive. Below — how much time you have and what happens if you keep going.
The electrical system is not holding voltage. While the engine runs the alternator carries it; shut it off and you may not restart.
Next the lights go, then modules start dropping out and false codes appear all over the truck. Get to somewhere with help without shutting the engine down.
Check the battery terminals and earth strap — corrosion and loose clamps throw false codes all over the truck. Running voltage should be 27–29 V.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.