Bendix EC-60 UDS 90 / SPN 1807 FMI 12 — SAS Invalid Signal

Code Details

Plain-English Meaning

The EC-60 detected a invalid signal from the steering angle sensor. The SAS signal is outside the expected range or contains data patterns the EC-60 cannot validate for use in ESP calculations. Without reliable steering angle data, ESP stability corrections are suspended.

The Bendix EC-60 table maps UDS code 90, blink code 21-06, J1587 089-12, and J1939 SPN 1807 FMI 12 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

• ESP/stability lamp on; steering-angle-dependent corrections suspended
• ABS and ATC continue normally
• Code may be persistent or intermittent
• Physical steering capability is unaffected
• May appear alongside YRS or LAS codes if sensors share a supply or calibration reference

Possible Causes

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

• SAS signal or supply wiring fault
• Corroded or partially-seated SAS connector
• YRS or model data discrepancy creating a plausibility disagreement with the SAS reading
• SAS internally failed — producing a fixed, out-of-spec, or erratic output
• Steering linkage wear allowing the SAS to see angles that do not match actual vehicle path

First Checks

• Use Bendix ACOM live data to observe SAS output during a slow controlled steering wheel movement — static, noisy, or reversed output is visible immediately.
• Inspect the SAS connector for corrosion, bent pins, or partial seating.
• Verify supply voltage and ground at the SAS connector.
• If the signal appears static, measure continuity of the CAN wires between SAS and EC-60 to identify a broken link.
• After any repair or calibration, clear codes and confirm smooth SAS angle tracking on ACOM live data.

Can I Keep Driving?

A stability sensor fault (yaw rate, steering angle, or lateral acceleration) disables ESP stability intervention while leaving ABS and ATC intact. The vehicle handles as it would without electronic stability control. Drive with that in mind — cornering, evasive maneuvers, and braking on slippery surfaces carry a higher risk. Stability sensor faults should be addressed before returning the vehicle to regular line-haul or severe-weather service.

Related Lookup Pages

• FMI 12 explanation
• Bendix manufacturer hub
• ABS / ATC / ESP fault codes
• ABS Light symptom page
• Brake Warning Light symptom page
• Search this code