Do not driveMinutes
J1939 code SPN 793. Below — how the fault is worded at the factory by Bendix ABS/ESP, Knorr-Bremse EBS, MAN, Meritor (ex-WABCO), Renault Trucks 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 TrucksWABCO ABS/ESC
| FMI 1 | AA Left WSS Excessive Air Gap |
| FMI 2 | AA Left WSS Open or Shorted |
| FMI 7 | AA Left WSS Wheel End |
| FMI 8 | AA Left WSS Erratic Sensor Signal |
| FMI 10 | AA Left WSS Loss of Sensor Signal |
| FMI 13 | AA Left WSS Tire Size Calibration; AA Left WSS Configuration Error |
| FMI 14 | AA Left WSS Output Low @ Drive-Off |
| FMI 4 | Sensor wheel speed, wheel 5. No signal |
| FMI 7 | Sensor wheel speed, wheel 5. Short |
| FMI 4 | Sensor wheel speed wheel 5 - No signal |
| FMI 7 | Sensor wheel speed wheel 5 - Closing |
| FMI 1 | AirGap Failure of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 3 | Short Circuit to UB of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 4 | Short Circuit to GND of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 5 | Interruption of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 6 | Shorted Coil of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 7 | Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 11 | Plausibility Check of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 13 | Failure Detection 'OverEquipped' of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 14 | RunOut Failure of Wheel Speed Sensor (Intermediate Axle Left) |
| FMI 1 | Speed sensor, left, additional axle, incorrect air gap. Repair: Check the sensor air gap. |
| FMI 2 | Speed sensor, left, additional axle, open circuit or short. Repair: Check the sensor resistance (950-1930 ohms). |
| FMI 7 | Speed sensor, left, additional axle, incorrect air gap or faulty tone wheel. Repair: Check the sensor air gap. Check the toothed wheel for tooth condition and axial run-out. |
| FMI 8 | Speed sensor, left, additional axle, signal lost while driving or ABS control fault. Repair: 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 | Speed sensor, left, additional axle, ABS control fault. Repair: Check the sensor resistance (950-1930 ohms). Check the toothed wheel for tooth condition and axial run-out. |
| 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 | 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.