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SPN 629 — Controller #1

Safe to driveTo the nearest safe stop

J1939 code SPN 629. Below — how the fault is worded at the factory by Bendix ABS/ESP, DAF, Dongfeng, Meritor (ex-WABCO), Renault Trucks, SITRAK and WABCO ABS/ESC, and what the second half of the code (FMI) means in the standard.

Bendix ABS/ESPDAFDongfengMeritor (ex-WABCO)Renault TrucksSITRAKWABCO ABS/ESC

Bendix ABS/ESP

FMI 2ECU (12); ECU (13); ECU (15); ECU (0D); Invalid ESP Configuration
FMI 12ECU (02); ECU (10); ECU (11); ECU (14); ECU (18); ECU (1A); ECU (1B); ECU (80); ECU (04); ECU (06); ECU (0E); ECU (37); ECU Internal VIN Mismatch
FMI 13Invalid ABS Configuration

DAF

FMI 12ECU D984 internal fault 2

Dongfeng

FMI 12Internal ECM malfunction

Meritor (ex-WABCO)

FMI 9Safety Controller Communication Faulty
FMI 11Trap Handler/Trap Set
FMI 12Pic Wdc/MC Error
FMI 14Watchdog/Reset Failure

Renault Trucks

FMI 2Internal control unit fault (EBS or ABS). Repair: Replace the ABS unit. Clear the fault codes. If the fault persists, replace the EBS unit.
FMI 9Internal control unit fault (EBS or ABS). Repair: Replace the ABS unit. Clear the fault codes. If the fault persists, replace the EBS unit.
FMI 11Internal control unit fault (EBS or ABS). Repair: Replace the ABS unit. Clear the fault codes. If the fault persists, replace the EBS unit.
FMI 12Internal control unit fault (EBS or ABS). Repair: Replace the ABS unit. Clear the fault codes. If the fault persists, replace the EBS unit.
FMI 13ABS unit internal fault. Repair: Replace the ABS unit.
FMI 14Fault storage process not completed. Repair: The power relay (R43) or the EECU is faulty.

SITRAK

FMI 0Real-time counter fault: counts faster or slower than allowed, or does not respond. Scan tool code: P1702. Effect: Torque limited, the engine may shut down.
FMI 1Read error in the non-volatile memory. Scan tool code: P1703. Effect: Torque limited, the engine may shut down.
FMI 4ECU internal fault: stack memory overrun. Scan tool code: P1706. Effect: Torque limited, the engine may shut down.
FMI 5ECU internal fault: irregular switch-off while the engine was running. Scan tool code: P1707. Effect: Torque limited, the engine may shut down.
FMI 8Error during the initialisation of an external device: no KeepAlive response. Scan tool code: P1701. Effect: Torque limited, the engine may shut down.
FMI 31COP fault

WABCO ABS/ESC

FMI 5No Loads Detected
FMI 8Excessive Slip
FMI 9Excessive Modulator Activation Time
FMI 12Internal Error
FMI 13Accelerometer Out of Range
FMI 14ECU Mounting, Accelerometer Not Plausible

What FMI means in J1939

SPN 629 FMI 0629/0 · 629.0data above normal range (most severe level)
SPN 629 FMI 1629/1 · 629.1data below normal range (most severe level)
SPN 629 FMI 2629/2 · 629.2data erratic or intermittent
SPN 629 FMI 4629/4 · 629.4voltage below normal or shorted to ground
SPN 629 FMI 5629/5 · 629.5current below normal or open circuit
SPN 629 FMI 8629/8 · 629.8abnormal frequency or pulse width
SPN 629 FMI 9629/9 · 629.9abnormal update rate
SPN 629 FMI 11629/11 · 629.11root cause not known
SPN 629 FMI 12629/12 · 629.12faulty device or component
SPN 629 FMI 13629/13 · 629.13calibration out of range
SPN 629 FMI 14629/14 · 629.14manufacturer-specific instructions
SPN 629 FMI 31629/31 · 629.31condition exists (see manufacturer description)

Can I keep driving

Safe to drive. Below — how much time you have and what happens if you keep going.

What happens if you keep driving

Time you have: To the nearest safe stop

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.

That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.

What to check on the spot

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.

Nearby: power supply

Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.