Bendix EC-60 UDS 129 / SPN 790 FMI 2 — SA Right WSS Open or Shorted

Code Details

Plain-English Meaning

The EC-60 found an open circuit or a short in the steer axle right wheel speed sensor circuit. Without a clean signal at that corner, ABS cannot control wheel braking there — ABS is suspended for that channel and ATC/ESP may be suspended as well.

The Bendix EC-60 table maps UDS code 129, blink code 03-03, J1587 002-02, and J1939 SPN 790 FMI 2 to this ABS/ATC/ESP diagnostic entry. The Bendix source indicates an ABS and/or ATC/ESP warning lamp can be on for this entry. The EC-60 continuously monitors wheel speed sensor circuits, pressure modulation valve output drivers, supply voltage quality, J1939 network data from the engine and transmission controllers, and internal self-diagnostic routines. When any monitored value falls outside its acceptable range — or a circuit does not respond as the module expects — the EC-60 logs a diagnostic trouble code and may disable the affected ABS, ATC, or ESP function. Bendix ACOM Pro or a compatible diagnostic interface is the required tool for reading live sensor data, running actuator tests, performing calibrations, clearing latched codes, and adjusting EC-60 configuration parameters. Generic J1939 scan tools can read the SPN/FMI but cannot access EC-60-specific live data screens or configuration settings.

Common Symptoms

• ABS warning lamp on
• ATC/ESP lamp on if stability functions are affected
• ABS inactive at the affected wheel corner; normal braking is unaffected
• Scan tool reads Bendix EC-60 UDS 129 / SPN 790 FMI 2 as active or stored
• Traction control may be suspended on the affected axle

Possible Causes

Possible causes may include the items below. The list is not a parts diagnosis.

• Wiring open between steer axle right WSS connector and EC-60 harness
• Short to ground or to battery voltage in the sensor circuit
• Corroded, bent, or backed-out terminal in the sensor connector
• Sensor coil internally open or shorted (passive sensors typically read 900–2000 Ω)
• Harness chafed on axle housing, suspension bracket, or chassis ground point

First Checks

• Inspect the steer axle right sensor connector for corrosion and bent pins before reaching for a meter.
• With ignition off and connector unplugged, measure sensor coil resistance — out-of-range reading condemns the sensor.
• Measure resistance from each sensor pin to chassis ground; any continuity indicates a short in the circuit.
• Trace the harness from sensor to EC-60 looking for abrasion on axle housing and air-line bundles.
• On the steer axle, trace the harness through the steering knuckle flex area — wire fatigue at the knuckle is a common cause of intermittent and hard open faults from repeated steering-cycle flexing.
• After repair, clear with Bendix ACOM or equivalent and confirm the code does not return on a test drive.

Can I Keep Driving?

ABS is disabled at the affected wheel channel while this fault is active. Normal hydraulic or air base braking continues unaffected — the vehicle can brake, but anti-lock protection is not available at that corner. Drive conservatively to a service location. Do not operate in conditions where ABS intervention would be likely, such as slippery surfaces or loaded highway braking. Clear only after root-cause repair.

Related Lookup Pages

• FMI 2 explanation
• Bendix manufacturer hub
• ABS / ATC / ESP fault codes
• ABS Light symptom page
• Brake Warning Light symptom page
• Search this code