SPN 970 — Engine Auxiliary Shutdown Switch

Safe to driveDrivable, but watch it yourself

J1939 code SPN 970. Below — how the fault is worded at the factory by KAMAZ, MAZ, Mercedes-Benz, Renault Trucks and YaMZ, and what the second half of the code (FMI) means in the standard.

KAMAZMAZMercedes-BenzRenault TrucksYaMZ

KAMAZ

FMI 3	Power stage shutoff monitor (watchdog path)
FMI 4	Power stage shutoff monitor (watchdog path)
FMI 12	Power stage shutoff monitor (watchdog path)

MAZ

FMI 3	Internal ECU fault - Supply voltage low. Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.
FMI 4	Internal ECU fault - Supply voltage exceeded. Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.
FMI 12	Internal ECU fault - Controller watchdog timer error. Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.

Mercedes-Benz

FMI 3	Engine Aux. Shutdown Input shorted to Ubat
FMI 4	Engine Aux. Shutdown Input shorted to GND

Renault Trucks

FMI 13	Injection cut-off path check through the power stages not carried out. Repair: The EECU is faulty, reprogram SOFT+DATA. If the fault appears again, replace the EECU.
FMI 14	Interrupt path check not performed with the internal supply too high or too low. Repair: The EECU is faulty, reprogram SOFT+DATA. If the fault appears again, replace the EECU.

YaMZ

FMI 3	Internal ECU fault (Supply voltage low). Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.
FMI 4	Internal ECU fault (Supply voltage exceeded). Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.
FMI 12	Internal ECU fault (Controller watchdog timer error). Blink code: 1-1-6. Power will be reduced. Repair: Replace the ECU.

What FMI means in J1939

SPN 970 FMI 3970/3 · 970.3	voltage above normal or shorted high
SPN 970 FMI 4970/4 · 970.4	voltage below normal or shorted to ground
SPN 970 FMI 12970/12 · 970.12	faulty device or component
SPN 970 FMI 13970/13 · 970.13	calibration out of range
SPN 970 FMI 14970/14 · 970.14	manufacturer-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: Drivable, but watch it yourself

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.

Nearby: other

• SPN 920Audible Alarm
• SPN 924Auxiliary Output #1
• SPN 925Auxiliary Output #2
• SPN 926Auxiliary Output #3
• SPN 928Axle Location
• SPN 972Accelerator Pedal Lockout (Limit Switch)
• SPN 974Remote Accelerator Pedal Position
• SPN 979Remote PTO Preset Speed Control Switch
• SPN 980PTO Enable Switch
• SPN 1041Start Signal Indicator

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