Bendix EC-60 UDS 122 / SPN 1808 FMI 2 — YRS Plausibility Check (Ref Yaw Rate)

Code Details

Plain-English Meaning

The EC-60 detected a yaw rate sensor plausibility error (vs the reference yaw rate). The EC-60 maintains a dynamic model that predicts the vehicle's expected yaw rate from wheel speeds, steering angle, and lateral acceleration — the actual YRS reading is compared against this prediction in real time. A plausibility error vs the reference yaw rate means the YRS and the EC-60's cross-check source disagree on the vehicle's current rotation rate. ESP yaw-correction is suspended until the disagreement falls within acceptable limits.

The Bendix EC-60 table maps UDS code 122, blink code 22-12, J1587 103-02, and J1939 SPN 1808 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

• ESP/stability lamp on; yaw-correction suspended
• ABS and ATC continue to operate normally
• Code may be intermittent, appearing during maneuvers or under specific temperature conditions
• Steering and braking physically unaffected — the fault is in the stability calculation, not the mechanical systems
• Multiple plausibility codes may appear together if several sensors disagree simultaneously

Possible Causes

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

• Long-term calibration drift that has accumulated past the inside-limits tolerance
• Temperature-related sensor output offset that has grown over time
• Calibration reference captured on a sloped or unlevel surface, causing a permanent offset from the true zero rate
• Alignment or suspension modification that changed vehicle dynamics without a recalibration
• Intermittent YRS CAN noise introducing transient errors that accumulate into a persistent plausibility fault

First Checks

• Inspect the YRS and its mounting bracket carefully for any sign of bending, cracking, or contact damage — plausibility faults are a classic symptom of bracket misalignment.
• Use Bendix ACOM live data to compare the actual YRS output to the model reference while the vehicle is stationary on level ground; a non-zero reading at rest confirms a calibration offset.
• Verify when the last calibration was performed and whether any chassis work has occurred since then.
• Perform a fresh YRS calibration on a confirmed level surface and recheck whether the inside-limits error persists.
• After any repair and recalibration, clear stored codes and test over a route that includes both straight-line and curved sections.

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