Traction Control Fault

[SNWAINE]

Hi all I'm having some serious problems with my 09 S-Max I brought it second hand from a garage with a new MOT with no advisories but 7 months down the line iv had to replace all the suspension and brakes plus both wish bones and tigh rods.

My only problem now is that traction Control will come on randomly and out of the blue, today it came on when doing 50mph down hill and it slow the car down to about 20mph very fast and harsh. There was also a slight knocking sound.

Dose any one have any ideas what it could be.

[KenM]

Probably an ABS sensor and the knocking sound was probably the ABS kicking in. Cheap enough fix if you have to replace a sensor but could also be a bad connection or wiring fault. Best bet is to get the fault codes read with something like Forscan.

[unofix]

3 hours ago, KenM said:

Probably an ABS sensor and the knocking sound was probably the ABS kicking in.

Totally agree. Once the system lost the signal from one of the ABS wheel sensors it would trigger the ABS pump to slow the car to a safe speed.

As Ken has said use FORScan to read the DTC and find out which wheel sensor is causing the problem. It could be a damaged wire, a corroded connector or simply a faulty sensor. Given the recent work that has been done on the vehicle this type of fault often occurs.

[SNWAINE]

Thank you both for yer help, iv run ForScan and this is the log.

It dose have some TDC's, what do you recommend?

Ford S-Max 09.txt

[KenM]

I would see if you can clear all the fault codes, take it for a drive and the read what fault codes show then, a lot of them could have been there a long time and not really relevant.

[unofix]

Hi Simon, now you have that list of DTC's many of which are very old, do what Ken has said. Use FORScan and clear all of the DTC's so that you can start fresh. Many of the codes "U" are a loss of canbus communication with different modules which can be caused by many different things and unless they keep reappearing are of no concern.

I notice that there are some ABS related codes and these may well be the one of interest if they come back after you clear the DTC's. Normally I'd expect FORScan to say that there is a problem with loss of comms with a particular wheel sensor.  

[SNWAINE]

Ok thank you, I'll clear the codes and drive for a bit just locally and then rescan.

The problem is the error with the braking can go a couple of days before it happens again, also when it dose happen it will do it a few times. I think it stops if I restart the car because each time it's happened and I've turned of the car and checked the car then return home. It would then be fine for a day or two. So yer very strange.

[SNWAINE]

Ok its happened a few times now and there is nothing coming up in the DTC's. Could there be anything else causing this as i would say the sound its makes when the light comes on is like a grinding sound and sounds as though it could be from the drivers side.

[KenM]

Have you tried reading dtc’s before turning the engine off.? But I would have thought any abs faults would have remained. I assume that all the previous faults have been cleared and none returned. It could be possible that one of the reluctor rings could be rusted up a bit and the abs sensor is misreading this at times as a wheel trying to lock up and the abs acting on that wheel. If you think you might know what wheel it is remove the sensor and see if you can see inside to the reluctor and turn the wheel completely to see what it’s like. I think if you had a faulty sensor or wiring there would have been something logged

[SNWAINE]

No iv only read the codes after turning off the car, I'll try that next and I'll have a look that part your talking about. Could it be a drive shaft issue as I noticed the car sounds louder than normal and the inner boot on the drivers side drive shaft had been fastened with a cable tie indicating it had come off or replaced.

[unofix]

1 hour ago, KenM said:

It could be possible that one of the reluctor rings could be rusted up a bit and the abs sensor is misreading this at times as a wheel trying to lock up and the abs acting on that wheel.

That's worth investigating 👍

[KenM]

Are you sure it’s the driveshaft making the noise and not the wheel bearing? Play in the wheel bearing would be more likely to cause abs problems.

[Gleen]

had exactly the same problem with my wife's 09 diesel auto s max.  The traction control light would come on, putting on diagonally operated brakes, and also

various error messages would appear at different times such as 'diesel filter overcharged' .. 'auto transmission requires service' .. and sometimes the engine management light would come on and stay on.

 

Turning the ignition off and back on cleared the fault for a while.  Sometimes whilst driving the car felt a bit 'flat' - that was without any warning lights or messages.

The fault, apparently, was the turbo. My local workshop cleaned the vanes which has resulted in a car with oomph .. and no warning lights or messages appearing.  No new parts were required.

No ABS fault was ever found on a diagnostics check.  Seemingly one fault ( a dirty turbo, for want of a better description) can cause error messages further down the line..

As for a knocking noise.. the workshop who did the job also replaced an engine mount.  They said I must have noticed the knock/vibration.  No, I  hadn't .. but the old engine mount certainly was well past it.

[SNWAINE]

Hi all thanks for all the help, i thought i should give a quick update. The issue was a small pinch in the wire for the ABS censor. The garage that did the work on the suspension must of pinched it but no way of proving it. its all fixed now and working fine thank you.