Do not driveMinutes
J1939 code SPN 37. Below — how the fault is worded at the factory by Ford Trucks and ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.
Ford Trucks/Ecotorq writes fault numbers in its own format: the code in the table below is a Ford code (hexadecimal, zero-padded), not a J1939 SPN. It matches the standard only where the signal itself is standard, and usually matches the title of this page by digit alone.
| FMI 0 | Alternator Electrical – Open Circuit. FODP code (scan tool): P0620-0D. |
| FMI 1 | Alternator Electrical – Short to Power. FODP code (scan tool): P0620-0C. |
| FMI 2 | Alternator Electrical – Ground Short. FODP code (scan tool): P0620-0B. |
ZF AS-Tronic uses its own fault numbering: the number in the table below is an internal ZF code, not a J1939 SPN. It matches the title of this page by digit only and means something different.
| FMI 10 | Fault on valve Y5 output circuit (range selector valve). |
Do not drive. Stop as soon as it’s safe to do so — don’t keep going.
Part of the brake circuit or ABS/EBS is out of service. The pedal may still feel normal — until the first emergency stop or descent.
Next comes longer stopping distance, a skid on a slick surface, failure on a long downgrade. This is the case where "I will take it slow" does not work.
Let the air system build to working pressure and listen for leaks. Don’t drive with faulty brakes.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.