Do not driveMinutes
J1939 code SPN 790. Below — how the fault is worded at the factory by Bendix ABS/ESP, Knorr-Bremse EBS, MAN, Meritor (ex-WABCO), Renault Trucks, SITRAK and WABCO ABS/ESC, and what the second half of the code (FMI) means in the standard.
Bendix ABS/ESPKnorr-Bremse EBSMANMeritor (ex-WABCO)Renault TrucksSITRAKWABCO ABS/ESC
| FMI 1 | SA Right WSS Excessive Air Gap |
| FMI 2 | SA Right WSS Open or Shorted |
| FMI 7 | SA Right WSS Wheel End |
| FMI 8 | SA Right WSS Erratic Sensor Signal |
| FMI 10 | SA Right WSS Loss of Sensor Signal |
| FMI 13 | SA Right WSS Tire Size Calibration |
| FMI 14 | SA Right WSS Output Low @ Drive-Off |
| FMI 4 | Sensor wheel speed, wheel 2. No signal |
| FMI 7 | Sensor wheel speed, wheel 2. Short |
| FMI 4 | Sensor wheel speed wheel 2 - No signal |
| FMI 7 | Sensor wheel speed wheel 2 - Short |
| FMI 1 | AirGap Failure of Wheel Speed Sensor (Front Axle Right) |
| FMI 3 | Short Circuit to UB of Wheel Speed Sensor (Front Axle Right) |
| FMI 4 | Short Circuit to GND of Wheel Speed Sensor (Front Axle Right) |
| FMI 5 | Interruption of Wheel Speed Sensor (Front Axle Right) |
| FMI 7 | Wheel Speed Sensor (Front Axle Right) |
| FMI 11 | Plausibility Check of Wheel Speed Sensor (Front Axle Right) |
| FMI 13 | Failure Detection 'OverEquipped' of Wheel Speed Sensor (Front Axle Right) |
| FMI 14 | RunOut Failure of Wheel Speed Sensor (Front Axle Right) |
| FMI 1 | Front right wheel speed sensor — air gap too large. Repair: Check the sensor air gap. |
| FMI 2 | Front right wheel speed sensor — open or short circuit. Repair: Check the sensor resistance (950-1930 ohms). Check the continuity of the speed sensor wiring (X3/4, X3/5). |
| FMI 7 | Front right wheel speed sensor — large air gap or damaged tone wheel. Repair: Check the sensor air gap. Check the sensor air gap. Check the toothed wheel for tooth condition and axial run-out. |
| FMI 8 | Front right wheel speed sensor — signal lost while driving or implausible, ABS control disturbed. Repair: Check the sensor air gap and the toothed wheel. If the fault persists, replace the speed sensor. Check the sensor resistance (950-1930 ohms). Check the toothed wheel for tooth condition and axial run-out. Check that there is no residual pressure in the brake chambers. Check the brake mechanisms for mechanical binding. |
| FMI 10 | Front right wheel — ABS control fault or tone wheel defect. Repair: Check the sensor resistance (950-1930 ohms). Check the toothed wheel for tooth condition and axial run-out. Check the condition of the toothed wheel. |
| FMI 12 | ABS unit internal fault. Repair: Replace the ABS unit. |
| FMI 13 | Wheel size mismatch (difference above 30%). Repair: Check the tyre size. Drive a few kilometres. If the faults persist, change the tyre size. |
| FMI 1 | Wheel speed sensor (front right): sensor air gap too large (signal below normal) |
| FMI 2 | Wheel speed sensor (front right): unstable data / bus error (deviation >10-14%) |
| FMI 3 | Wheel speed sensor (front right): sensor short circuit to battery (voltage above normal) |
| FMI 4 | Wheel speed sensor (front right): sensor short circuit to ground (voltage below normal) |
| FMI 5 | Wheel speed sensor (front right): sensor circuit open (current below normal) |
| FMI 6 | Wheel speed sensor (front right): internal sensor short circuit (current above normal / short to ground) |
| FMI 7 | Wheel speed sensor (front right): sensor/tone ring periodicity error |
| FMI 8 | Wheel speed sensor (front right): abnormal signal frequency/amplitude/period |
| FMI 9 | Wheel speed sensor (front right): abnormal or missing signal, harness miswired |
| FMI 10 | Wheel speed sensor (front right): wheel speed signal lost |
| FMI 11 | Wheel speed sensor (front right): wheel speed abnormal |
| FMI 12 | Wheel speed sensor (front right): tone ring damaged / abnormal rotational frequency |
| FMI 1 | Air Gap |
| FMI 2 | Incorrect Tire |
| FMI 3 | Shorted to UBATT |
| FMI 4 | Shorted to Ground |
| FMI 5 | Open Circuit |
| FMI 6 | Short Circuit |
| FMI 7 | Incorrect Tone Ring |
| FMI 8 | Excessive Slip |
| FMI 9 | Wires Mismatched |
| FMI 10 | Speed Drop-Out |
| FMI 11 | Abnormal Speed (Chatter) |
| FMI 12 | Frequency Too High |
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.