IS THIS A VALID M.O.T. ADVISORY?

RBZ5416

I had an intermittent ABS warning on my old E46 (2000) & that not only logged the fault but also which wheel. But like yours, would never misbehave when being investigated. It finally turned into a solid error so I had to fix it for the next MOT by replacing the sensor.
Your call but it potentially gives you evidence for the dealer. As you say, the easy way out for the dealer is to declare NFF right up to the point the warranty expires. Nothing to stop them simply resetting any stored errors rather than actually investigating them.

absolutely80s

Interesting. In my case, a sensor has ben replaced, but the problem persists. Brings to question how detailed the one hour of diagnostic work (term of the warranty) actually was. Yes, I could get a code reader, but at the end of the day, I imagine the dealer will still use their default position of "if it doesn't happen under our care, it can't be a problem". I'm exceedingly keen to see the outcome of the independent check tomorrow.

Bl4ckGryph0n

There you go. That is very important information. Does it always appear intermittently with the ESP light. That is exactly what I mean. The combination of those lights will have different meaning than when the light is on by itself. And for some brands it depends on where it is on, what colour it is, whether it is static etc.

The entirety of the situation is important. Now you say it only comes one together with ESP does that mean it’s defective, or that it is active. Perhaps your user guide may give some indication.

absolutely80s

Yes, the two lights come on together, sporadically, and for seconds at a time. I can go a day without seeing them. The user guide provides no pointers, other than to say "get it looked at asap" (rather than stop driving NOW). Given that I trusted Ford to have previously and properly investigated when they replaced a sensor last month, I'm inclined to feel they didn't do a thorough job in their warrantied one hour of diagnostic work.

IronGiant

A quick google suggests that both the ESP and the ABS system uses the same sensors, so if they both come on then it's likely to be a(nother) sensor.  Or a wiring issue, whereby some insulation has failed and water is getting in.  Anything else is likely to be expensive. Hopefully you'll find out tomorrow.

absolutely80s

Thanks, that’s kind of you too look into it. Clearly, that would be the best outcome. We shall see. I’ll post again tomorrow no doubt....

gibbo52

For me the fact the dealer changed a sensor suggests a fault code was stored, the problem could be that just because the scanner says it has a faulty sensor doesn't necessarily mean that the sensor is faulty.

absolutely80s

Ok, but the under car noise is still prevalent, even if on an ad hoc basis. Independent garage man feels it’s abs related, and if it is, that may explain the continued warning lights. But will see what happens tomorrow.

AMc

Indeed - recently had an ABS/ESP warning on the Mini.  The fault would light up on a fast right turn then clear itself on restart.  It was duly checked and the sensor was fine, the front left wheel bearing was worn and under load it was upsetting the speed sensor.
New wheel bearing was needed but the mechanic was unable to free the sensor without destroying it so a new sensor too.

mij

I have seen this happen with warped disks at speed, everything is ok at lower speed as less vibration.