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SPN 633 — Fuel Delivery Actuator Control Command 1

Safe to driveTo the nearest safe stop

J1939 code SPN 633. Below — how the fault is worded at the factory by DAF, Dongfeng and Isuzu, and what the second half of the code (FMI) means in the standard.

DAFDongfengIsuzu

DAF

FMI 31ECU D984 internal fault 4 (fuel injection pump valve B334)

Dongfeng

FMI 31Implausible solenoid valve resistance value

Isuzu

FMI 7Pressure limiter open (P1095)

What FMI means in J1939

SPN 633 FMI 7633/7 · 633.7mechanical system not responding
SPN 633 FMI 31633/31 · 633.31condition 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

Fuel is not arriving in the right amount or at the right pressure. It shows up first on climbs and under load.

You will most likely stall out on the road, and may not restart on the shoulder. A clogged filter or water in the tank you can nurse to a shop; a failing injection pump you cannot.

What to check on the spot

Check the fuel filter and water trap, drain the water. In cold weather, suspect fuel waxing.

Nearby: fuel

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