SAE J1939 SPN and FMI fault codes for chassis and suspension systems. Covers air suspension controllers, electronic steering, tire pressure monitoring, wheel speed sensors, and vehicle dynamic stability control on heavy-duty commercial vehicles.
Diagnostic Code SPN 790 FMI 5: Meaning and Fix This fault indicates an open circuit or current below normal threshold in the right front ABS wheel sensor circuit on axle 1. The ECM cannot receive proper wheel speed data from this sensor. Technicians commonly encounter this code after winter operations where salt corrosion affects sensor … Read more
Diagnostic Code SPN 792 FMI 2: Meaning and Fix The SPN 792 FMI 2 fault code indicates erratic or incorrect data from the ABS wheel sensor on axle 2 right. This typically arises in situations such as post-maintenance realignment or after replacing suspension components. Technicians often encounter this fault when the sensor is improperly calibrated … Read more
Diagnostic Code SPN 1592 FMI 19: Meaning and Fix SPN 1592 FMI 19 indicates corrupted network data transmission from the front axle left wheel speed sensor to the ABS control module. This fault commonly appears after ECM reprogramming or following electrical system maintenance when CAN bus integrity becomes compromised. The high-resolution speed measurement critical for … Read more
Diagnostic Code SPN 1059 FMI 2: Meaning and Fix SPN 1059 FMI 2 indicates the Axle Load Sensor is sending erratic, intermittent, or incorrect data to the ECM. This fault often appears after a vehicle has undergone a suspension repair or wheel alignment, where the sensor linkage is disturbed. Technicians may notice the payload display … Read more
Diagnostic Code SPN 1807 FMI 2: Meaning and Fix SPN 1807 FMI 2 is triggered when the steering wheel angle sensor sends erratic or incorrect data, often following electrical interference or sensor misalignment. This code affects the vehicle’s dynamic stability control, leading to potential steering anomalies. Technicians often encounter this fault after steering column repairs … Read more
Diagnostic Code SPN 791 FMI 2: Meaning and Fix SPN 791 FMI 2 indicates erratic, intermittent, or incorrect data from the left wheel speed sensor on axle 2. This fault commonly appears during wet weather conditions when contaminated sensor rings generate inconsistent pulse signals. The ECM detects irregular frequency patterns that don’t correlate with vehicle … Read more