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SPN 653 — Engine Injector, Cylinder #03

Updated: 2026-11-10

Safe to driveTo the nearest safe stop

J1939 code SPN 653. Below — how the fault is worded at the factory by Cummins ISB, DAF, Dongfeng, Isuzu, KAMAZ, KAMAZ-5490, MAZ, Renault Trucks and YaMZ, and what the second half of the code (FMI) means in the standard.

How to check it yourself

The electrical circuit of injector 3 — the third from the fan, nearer the middle of the head. On an in-line six it fires 3rd in the 1-5-3-6-2-4 order: after 5 and before 6. The injector wires run under the valve cover.

What it should read

Solenoid injector: winding resistanceusually a fraction of an ohm, about 0.2…0.6 Ω — per the factory data
Piezo injectorhundreds of kΩ — do not compare with a solenoid one
Wire resistance to the bodyinfinity

Check order

  1. Check whether there are codes for other injectors. If several cylinders of the 1–3 group show at once — on many ECUs they share a supply wire: look there and at the connector on the head, not in the injector.
  2. FMI 3, 4, 5, 6 (open or short): unplug the harness connector on the head, measure the winding of injector 3 and compare it with the neighbouring injector 2. Measure twice — at the head connector and directly at the injector: the difference is the wire under the cover.
  3. The wire under the valve cover: oil and heat make the insulation brittle, and it chafes against the rocker. The nuts on the injector terminals — tighten by hand; over-tightened ones snap the stud.
  4. FMI 7, 11, 12, 14 (injector not responding): swap injector 3 into cylinder 2. If the code moves with the injector — the injector; if it stays — the wire or the ECU.
  5. Also check the misfires in this cylinder — SPN 1325.

Common causes — from most to least frequent

  1. Wire under the valve cover: chafed, dried out, burnt terminal.
  2. Harness connector on the head — oil inside the connector.
  3. Injector winding.
  4. Shared supply wire of the 1–3 group — if the code is not the only one.
  5. ECU output — only after everything else has been checked.

Cummins ISBDAFDongfengIsuzuKAMAZKAMAZ-5490MAZRenault TrucksYaMZ

Cummins ISB 6.7 engine

FMI 5Injector solenoid driver cylinder 3 circuit current low or open
FMI 7Injector solenoid driver cylinder 3, mechanical system not responding

DAF

FMI 5Cylinder #3 injector open circuit/short to ground
FMI 7Cylinder #3 injector mechanical fault

Dongfeng

FMI 5Fault in injector 3 circuit

Isuzu

FMI 3Open circuit in injection nozzle #3 drive system (P0203)

KAMAZ engine (J1939)

FMI 3Cylinder 3 injector: fault / warning
FMI 5Cylinder 3 injector.
FMI 6Cylinder 3 injector.
FMI 7Cylinder 3 injector.
FMI 8Cylinder 3 injector: fault / warning
FMI 11Cylinder 3 injector: fault / warning
FMI 12Cylinder 3 injector: fault / warning.
FMI 14Cylinder 3 injector.

KAMAZ-5490 (Mercedes, K-line)

FMI is per the block maker's own table, not the J1939 table below.

FMI 5Injector cylinder 3: open circuit. K-line code on KamAZ-5490: MR2 15227.
FMI 6Injector cylinder 3: circuit short. K-line code on KamAZ-5490: MR2 15228.
FMI 7Injector cylinder 3: injection timing, no delivery. K-line code on KamAZ-5490: MR2 15226.
FMI 12Injector cylinder 3: idle control in limit. K-line code on KamAZ-5490: MR2 19244.
FMI 14Injector cylinder 3: cylinder correction in limit. K-line code on KamAZ-5490: MR2 19245.

MAZ

FMI 3Cylinder 3 injector driver circuit fault - Negative wire shorted to battery. Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 8Cylinder 3 injector driver circuit fault - Negative wire shorted to positive wire. Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 11Cylinder 3 injector driver circuit fault - Depends on calibration. Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 12Cylinder 3 injector driver circuit fault - Open circuit. Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.

Renault Trucks

FMI 3Injector 3, cylinder 3, short to battery voltage. Repair: Check the injector (impedance at 20 °C from 0.3 to 0.5 ohms) and the wiring (A 24, A 40, A 41).
FMI 4Cylinder 3 injector (unit pump) — short to ground or open circuit. Repair: Check the pump winding and the wiring (J 1/23, J 1/42). Check the injector (impedance at 20 °C from 0.3 to 0.5 ohms). Check injectors 1, 2 and 3.
FMI 5Injector 3, cylinder 3, open circuit. Repair: Check the injector (impedance at 20 °C from 0.3 to 0.5 ohms).
FMI 8Pump or injector of cylinder 3, mechanical fault. Repair: Mechanical fault.
FMI 11Injector 3, cylinder 3, unidentified fault. Repair: Check the injector (impedance at 20 °C from 0.3 to 0.5 ohms) and the wiring (A 24, A 40, A 41). If the fault persists, replace the EECU.

YaMZ

FMI 3Cylinder 3 injector driver circuit fault (Negative wire shorted to battery). Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 8Cylinder 3 injector driver circuit fault (Negative wire shorted to positive wire). Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 11Cylinder 3 injector driver circuit fault (Calibration dependent). Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.
FMI 12Cylinder 3 injector driver circuit fault (Open circuit). Blink code: 1-4-3. Power will be reduced. Repair: Check the injector connectors and harness.

What FMI means in J1939

SPN 653 FMI 3653/3 · 653.3voltage above normal or shorted high
SPN 653 FMI 4653/4 · 653.4voltage below normal or shorted to ground
SPN 653 FMI 5653/5 · 653.5current below normal or open circuit
SPN 653 FMI 6653/6 · 653.6current above normal or grounded circuit
SPN 653 FMI 7653/7 · 653.7mechanical system not responding
SPN 653 FMI 8653/8 · 653.8abnormal frequency or pulse width
SPN 653 FMI 11653/11 · 653.11root cause not known
SPN 653 FMI 12653/12 · 653.12faulty device or component
SPN 653 FMI 14653/14 · 653.14manufacturer-specific instructions

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.

This is an electrical fault: an open, a short or a bad contact in the sensor circuit. The value it measures is most likely fine. You can drive. But until the circuit is repaired this system runs blind and cannot warn you about a real failure.

What to check on the spot

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

Where to start

This code is often not the fault itself but a knock-on. If any of these is in the same readout, start with it:

Nearby: fuel

Makes with this code

KAMAZMAZYaMZDongfengDAFRenault TrucksIsuzuCummins ISBKAMAZ-5490

Related problems

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