Safe to driveTo the nearest safe stop
J1939 code SPN 801. Below — how the fault is worded at the factory by Bendix ABS/ESP, Meritor (ex-WABCO), Renault Trucks and WABCO ABS/ESC, and what the second half of the code (FMI) means in the standard.
Bendix ABS/ESPMeritor (ex-WABCO)Renault TrucksWABCO ABS/ESC
| FMI 2 | Retarder Relay or HSA Lamp Open Circuit |
| FMI 3 | Retarder Relay Circuit or HSA Lamp Shorted to Voltage |
| FMI 3 | Failure detection 'ShortUb' at Endurance Brake Relay |
| FMI 4 | Failure detection 'ShortGnd' at Endurance Brake Relay |
| FMI 5 | Failure detection 'Interruption' at Endurance Brake Relay |
| FMI 13 | Failure detection 'OverEquipped' at Endurance Brake Relay |
| FMI 3 | Retarder cut-off relay supply, open circuit or short. Repair: Check the continuity of the wiring of the retarder cut-out relay circuit R18 (X1/17) (fuse F28 20 A). |
| FMI 4 | Retarder cut-off relay supply, short to ground. Repair: Check the continuity of the wiring of the retarder cut-out relay circuit R18 (X1/17) (fuse F28 20 A). |
| FMI 11 | Relay R18: contact or relay fault, open circuit at the contact or at the relay. Repair: Make sure the relay operates correctly. |
| FMI 3 | Shorted to UBATT |
| FMI 5 | Open Circuit |
| FMI 6 | Shorted to Ground |
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.