Safe to driveTo the nearest safe stop
J1939 code SPN 650. Below — how the fault is worded at the factory by Renault Trucks, and what the second half of the code (FMI) means in the standard.
| FMI 3 | Power relay, short to positive. Repair: Check the continuity and insulation of the wiring with respect to +24 V (SL3/9). |
| FMI 4 | Power relay, open circuit or short to ground. Repair: Check the continuity and insulation of the wiring with respect to ground (SL3/9). Carry out this check at least 10 seconds after switching the ignition off. |
| FMI 5 | Power relay, open circuit: the relay must be closed when the ignition is on. Repair: Check the continuity and insulation of the wiring (SL3/9). |
| FMI 7 | Power relay stuck in the closed or the open position. Repair: Make sure the relay operates correctly, check the fuse. Make sure the relay operates correctly. |
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.