Code Details
| Display code | WABCO RSSplus SID 6 FMI 10 |
|---|---|
| SPN | Not applicable or not verified |
| FMI | 10 |
| OEM code | WABCO / ZF SID 6 FMI 10 |
| Manufacturer | WABCO / ZF |
| System | Trailer ABS / RSSplus |
| Component | Wheel Sensor f |
| Source address | Unknown or not applicable |
| Severity | high |
| Review status | ai source checked |
| Source confidence | high |
| Last reviewed | 2026-04-09 |
Plain-English Meaning
A dropout is different from a complete open circuit (FMI 5): the sensor had been producing a signal, and then the signal cut out for a period before potentially returning. This intermittent behavior is characteristic of a connector that is making poor contact, a wire that has broken internally but is held in position by the insulation, or a sensor that is mechanically loose and can disconnect as the trailer moves.
WABCO MM-0888 FMI 10 flags a signal dropout for Wheel Sensor f. The ECU distinguishes between a circuit that has never produced a signal (hard open, typically FMI 5) and one that produced a valid signal and then lost it. This distinction narrows the fault to an intermittent condition in an otherwise functional circuit.
Common Symptoms
- Trailer ABS lamp may be intermittent — activating at speed or during vibration and clearing at rest
- Signal dropout visible in WABCO PC diagnostics for wheel F as a speed that cuts to zero then recovers
- May correlate with specific speed ranges, rough road, or loaded vs. empty trailer conditions
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Loose sensor connector at the wheel end — the most common cause of dropouts that correlate with road vibration
- Internal wire break held together by insulation that opens under harness flexing
- Sensor not fully seated in the mounting bracket, allowing movement that changes the air gap intermittently
- Connector terminal with reduced retention force (spread contact) that breaks contact under vibration
First Checks
- While monitoring live sensor data in WABCO PC diagnostics, wiggle the sensor F connector and harness — a dropout that appears under harness movement confirms the intermittent connection location.
- Ensure the sensor is fully seated in its bracket and the locking clip is engaged — a sensor that can move axially will change its air gap as the wheel end moves.
- Inspect the connector locking mechanism and terminal seating — push each terminal gently to confirm it is fully seated with no play.
- Flex the harness through its full range of motion at each known flex point — suspension arm, brake spider clearance, frame bracket — to isolate any flex-induced breaks.
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
Why does WABCO RSSplus SID 6 FMI 10 appear at highway speed but not at lower speeds?
Higher vehicle speeds increase harness vibration amplitude. A connector with marginal contact may maintain continuity at low speed but lose contact under the higher vibration frequency at highway speed. The correlation with specific speed ranges can point to which harness segment is the cause.
Can a dropout be caused by the sensor itself rather than the harness?
Yes. Active sensors can have internal intermittent faults — particularly if the sensor has been impacted, has moisture ingress, or has developed a cracked bond wire inside the sensor body. If the harness and connector check out under wiggle-testing, replacing the sensor is the next step.
Is a code that clears itself a lower priority than a persistent code?
Not necessarily for safety-critical systems. An intermittent dropout means ABS may not be functioning correctly on wheel F at certain times. An ABS system that works only intermittently is not providing the protection it was designed for. Intermittent codes on ABS-related circuits should be investigated with the same priority as persistent codes.