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SPN 3512 — Sensor Supply Voltage 4

Safe to driveTo the nearest safe stop

J1939 code SPN 3512. Below — how the fault is worded at the factory by DAF, Dongfeng, MAZ, SITRAK and YaMZ, and what the second half of the code (FMI) means in the standard.

DAFDongfengMAZSITRAKYaMZ

DAF

FMI 35V sensor supply voltage too high at ECU pin B27
FMI 45V sensor supply voltage too low at ECU pin B27

Dongfeng

FMI 3Sensor No. 4 supply voltage too high. Scan tool code: P1602.
FMI 4Sensor No. 4 supply voltage too low. Scan tool code: P1603.

MAZ

FMI 312V sensor supply voltage fault - Sensor supply voltage high. Blink code: 1-3-1. Repair: Check the harnesses and the sensors connected to the engine ECU.
FMI 412V sensor supply voltage fault - Sensor supply voltage low. Blink code: 1-3-1. Repair: Check the harnesses and the sensors connected to the engine ECU.

SITRAK

FMI 2Sensor supply module 4 failure. Scan tool code: P06A3. Effect: Torque may be limited.
FMI 3Internal sensor supply voltage too high. Scan tool code: P1602.
FMI 4Internal sensor supply voltage too low. Scan tool code: P1603.
FMI 5Undervoltage at sensor supply 4. Scan tool code: P06A3. Effect: Torque may be limited.
FMI 6Overvoltage at sensor supply 4. Scan tool code: P06A3. Effect: Torque may be limited.
FMI 13Over-temperature at sensor supply 4. Scan tool code: P06A3. Effect: Torque may be limited.

YaMZ

FMI 312V sensor supply voltage fault (Sensor supply voltage high). Blink code: 1-3-1. Repair: Check the harnesses and the sensors connected to the engine ECU.
FMI 412V sensor supply voltage fault (Sensor supply voltage low). Blink code: 1-3-1. Repair: Check the harnesses and the sensors connected to the engine ECU.

What FMI means in J1939

SPN 3512 FMI 23512/2 · 3512.2data erratic or intermittent
SPN 3512 FMI 33512/3 · 3512.3voltage above normal or shorted high
SPN 3512 FMI 43512/4 · 3512.4voltage below normal or shorted to ground
SPN 3512 FMI 53512/5 · 3512.5current below normal or open circuit
SPN 3512 FMI 63512/6 · 3512.6current above normal or grounded circuit
SPN 3512 FMI 133512/13 · 3512.13calibration out of range

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.

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.