Code Details
| Display code | WABCO RSSplus SID 5 FMI 11 |
|---|---|
| SPN | Not applicable or not verified |
| FMI | 11 |
| OEM code | WABCO / ZF SID 5 FMI 11 |
| Manufacturer | WABCO / ZF |
| System | Trailer ABS / RSSplus |
| Component | Wheel Sensor e |
| Source address | Unknown or not applicable |
| Severity | high |
| Review status | ai source checked |
| Source confidence | high |
| Last reviewed | 2026-04-09 |
Plain-English Meaning
The ECU is receiving a noisy signal from sensor E that has rapid fluctuations superimposed on or replacing the expected wheel-speed pulse train. This is not a missing signal or a shorted circuit — the signal is present but electrically noisy. Electromagnetic interference from other trailer electrical systems, a poorly grounded harness, or a damaged sensor cable are the most common causes.
WABCO MM-0888 FMI 11 is listed as 'abnormal speed signal or chatter' for Wheel Sensor e. The ECU's signal processing distinguishes between the expected pulse frequency band (based on wheel speed) and high-frequency noise outside that band. Chatter that exceeds the ECU's noise threshold triggers FMI 11.
Common Symptoms
- Trailer ABS lamp on or intermittently active
- Noisy, irregular waveform on wheel E channel in WABCO PC diagnostics — signal may appear as a high-frequency hash rather than clean pulses
- May correlate with specific trailer lighting, refrigeration unit, or other electrical system operation
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Electromagnetic interference from nearby trailer lighting, refrigeration unit power cabling, or converter-inverter wiring
- Sensor harness not separated from high-current trailer wiring — parallel routing of sensor and power wires over long distances
- Poor trailer chassis ground causing noise to couple into the sensor return circuit
- Damaged sensor cable shield (on shielded sensor cables) — a broken shield allows external noise to enter the signal circuit
First Checks
- Note whether WABCO RSSplus SID 5 FMI 11 correlates with specific electrical loads: trailer lights on vs. off, refrigeration unit operating vs. off — interference sources are often identifiable by correlation.
- Check whether the sensor harness is routed close to and parallel with high-current wiring (lighting power, refrigeration unit supply cables) and whether a separation or re-routing is needed.
- Check trailer chassis ground quality — measure resistance from the ABS ECU ground to the trailer frame and to the kingpin/coupling point.
- If the harness uses a shielded cable, check shield continuity and that the shield is properly terminated at one end only (per WABCO installation guidelines).
Can I Keep Driving?
Trailer ABS and brake-related codes should be handled conservatively. Stop safely for brake warnings, red stop lamps, abnormal braking, wheel-end concerns, or any severe warning condition, and follow fleet or OEM guidance.
Related Lookup Pages
Sources
- WABCO RSSplus Trailer ABS Maintenance Manual MM-0888 WABCO / ZF Commercial Vehicle Solutions · oem · accessed 2026-05-05 · confidence high
Source: WABCO / ZF Commercial Vehicle Solutions, WABCO RSSplus Trailer ABS Maintenance Manual MM-0888. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - TOOLBOX PLUS Diagnostic Software ZF Commercial Vehicle Solutions · oem · accessed 2026-05-05 · confidence medium
Source: ZF Commercial Vehicle Solutions, TOOLBOX PLUS Diagnostic Software. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
Can a refrigeration unit cause WABCO RSSplus SID 5 FMI 11?
Yes. Refrigeration units generate significant electrical noise, particularly from their inverter and electric motor drive circuits. If the reefer unit's power wiring runs parallel to the ABS sensor harness over a long section of the trailer frame, inductive coupling can inject noise into the sensor circuit. Separating the wiring runs and ensuring proper grounding are the primary mitigations.
Does WABCO RSSplus SID 5 FMI 11 affect all four wheel sensors or just one?
Interference from a common noise source (chassis ground issue, parallel wiring) can potentially affect multiple sensors, but the FMI 11 code is logged per channel. If multiple wheels show FMI 11, a systemic electrical issue is more likely than individual sensor faults.
Will shielded sensor cable fix WABCO RSSplus SID 5 FMI 11 reliably?
Shielded cable reduces susceptibility to electromagnetic interference but does not eliminate all noise. The shield must be properly terminated and the shield continuity must be intact. A damaged or improperly installed shield provides little benefit. Shielded cable combined with proper harness routing and solid grounding is the most effective combination.