Technical Auto Cruise failure ?

Currently reading:
Technical Auto Cruise failure ?

Monty205

Member
Joined
Apr 8, 2014
Messages
33
Points
58
I have a 2013 Adria coach-built Motorhome based on the Ducato 130 Multijet.

The last major holiday trip was down to Spain and back in September 2019. At that time everything worked as it should.

Thanks to the pandemic, the vehicle has been little-used since that time. It has however been given a 20 or 3o mile run-out at least twice, and often more frequently, each month, just to keep things 'lubricated' so to speak.

Last time out, on the M6, the Auto-Cruise system failed to function.

In 5th and 6th gear, when I turned the system on, the green indicator light on the dash illuminated as it should, but operating the lever failed to encourage the system to function.

No other warning lights appear, and there are no 'Error Codes' showing.

Is there anything I can check easily, before I throw myself on the mercy of the local dealership who will probably rip me off unmercifully ?
 
Having never seen an error code, I assumed that it would show up as some sort of indication somewhere on the dash cluster, although thinking about it, I suppose it will only be visible once the requisite gizmo is connected to enable system diagnosis to take place?

Turning the device on, is usually only necessary on clear Motorways or Autoroutes, and so it does not get used very often in the UK, but in France and Spain I use it all the time. I turn it on once I have accessed the Autoroute and attained cruising speed - 65 mph, or thereabouts.
 
I accelerate to 65mph.

I am now in 6th gear.

I rotate the bezel on the end of the control stalk.

The green indicator light on the instrument panel illuminates.

I push the control stalk 'up' for the required time period, and remove my foot from the accelerator pedal.

There is no response from the Cruise Control system, and the vehicle starts to slow down.

As an aside, it can not be related to fuses as the ESP and ABS, amongst other things, utilise the same fuse, and surely the green warning light on the instrument panel would not be illuminated if the fuse had blown.

If ESP/ABS had failed I would have some sort of warning on the instrument panel.

I am starting to save my pocket money, in order to pay the exorbitant repair costs, although to be honest, as things stand, I will have plenty of time to save up as it is extremely unlikely that the motorhome will be going anywhere for at least the next 6 months ?
 
The brake pedal and the clutch pedal both have a switch that knocks off the c/c they can stick try some wd40 on them both, you will need to stand on your head to see them towards the top of the pedals arm.

The other thing you can try is finding a quite bit of motorway slip you foot under the clutch pedal and lift it slightly and try the c/c again same with the brake pedal, this sometimes works as a pointer to a faulty switch.
 
Thanks for those tips chaps.

Before I do anything else I will check out those switches, and give the van a quick run down the motorway.
 
Just stood on my head to look for the switches in question, and I'm buggered if I can see owt ?


On the brake pedal I can sees a microswitch unit, which I imagine is for the brake lights. It is mounted so that the switch is permanently 'made', until the pedal is depressed, at which point it is activated.

I can see no other switch units on either brake or clutch pedal, .......... but then I don't know what I am looking for really.


Are there any illustrations anywhere that I could have a shuffti at ?
 
Just stood on my head to look for the switches in question, and I'm buggered if I can see owt ?


On the brake pedal I can sees a microswitch unit, which I imagine is for the brake lights. It is mounted so that the switch is permanently 'made', until the pedal is depressed, at which point it is activated.

I can see no other switch units on either brake or clutch pedal, .......... but then I don't know what I am looking for really.


Are there any illustrations anywhere that I could have a shuffti at ?

Yes you have been looking at the correct switch. Technically not a microswitch which by definition, only requires a small amount of travel in order to operate. The one that I fitted on my x244 in order to install cruise control is colored black and white. The brake light section of the switch is closed when taken out of the box, but held open when the switch is mounted. The opposite is true for the cruise control section, which must be seen as closed for the cruise control to operate. This is a safety function, so that the cruise control is disabled on braking.

The clutch pedal switch is similar at least for the x244, and again must be seen as closed for the cruise control.

I hope that if necessary, the removal of the brake pedal switch is easier than on the x244. See this thread, https://www.fiatforum.com/ducato/475377-x244-brake-light-switch-its-bitch.html?475377=#post4492711 and scroll towards the end for picture of switch. For more pictures of switches try searching on Ebay.
 
On the brake pedal, I can feel that the switch activates mechanically when the pedal is moved.

As for the clutch I can not locate any sort of switch.

Where should I be looking ?

It is a very inaccessible area, and being elderly and wearing varifocal specs does not help.
 
Hi,

A web and ebay search returned the following. https://www.ebay.co.uk/itm/Fits-Fia...e:Fiat&hash=item421861925a:g:B9cAAOSwyKNfqp8P

It differs from the clutch switch fitted to my x244, which is of similar construction to the brake pedal switch, previously linked to. It is however shown as a clutch pedal switch. Look for a harness of two wires only, in the clutch pedal pivot area. Perhaps a torch and mirror would help.

As has already been suggeted, Multicuscan could be used to interrogate the ECU, and check that the various inputs are functioning correctly.
 
This post contains affiliate links which may earn a commission at no additional cost to you.
OK, thanks for that.

I'll have another look in the morning, when my ageing joints have had a night's rest. (y)
 
Well I had another look yesterday, and am non the wiser.

The vehicle was booked in for MoT and Servicing today, and so I asked if they could run a diagnostic check on the cruise control.

I have just had a phone call, from the garage. They have carried out the service, and it passed the MoT, BUT after running the diagnostic check, the warning lights for the ABS appeared. They are out of time today, so they will continue to investigate tomorrow. They could not release the vehcile in that condition anyway.


I will ring the bank manager and organise an overdraft.
 
Hi Monty

I'm wondering if you have a faulty wheel speed sensor (or connection thereto). These are used by the ABS to determine wheel speed, but it's possible the cruise control system uses them too.

As a completely separate issue, people have often reported in the past that various dashboard warning lights (LEDs) glow dimly, and this can be affected by whether the sidelights are on or if the cruise control system is switched on or not. By dimly I mean hardly visible in daylight. This is a design fault/manufacturing shortcoming of the cluster and doesn't indicate any genuine faults, cause any problems or result in any error codes. It's mostly just irritating but I guess it might frighten an MOT tester if he spots it in a dark workshop. As a check, when you first turn on the ignition but before starting, the ABS light will come on (as self test) at its full brilliance, which should be MUCH brighter than in the spurious condition above.
 
Last edited:
Time will tell, and at £45/50 per hour it will reflect badly on my savings.

If it is one of the wheel sensors then it may not cost too much but on the matter of dashboard clusters, I have already had 5 replacements, and also forked out a small fortune for a complete replacement seat bag mechanism/gizmo.


On top of the ongoing costs relating to tyres, cam belts, and water pumps, this vehicle has been nothing but a drain on my dwindling OAP.


It may be time to offload it, if I can get it roadworthy.
 
The vehicle has been with the garage for a few days now, and in the end they called in a 'specialist techy chap' to try to diagnose the fault, which was eluding them..

I have now been informed that they are fairly certain that the root cause of the initial problem with the cruise control was down to the ABS pump, as some signal or other that the it either controls or receives or whatever, is governed by this gizmo.

It is very expensive to replace, with an original Fiat part, and they have suggested that they remove the unit from the vehicle and have it repaired by a specialist company that they use, with a degree of monotony, in relation to failed Fiat Ducato vehicle electronic parts.

If it can not be repaired, and they tell me that this is always possible, then I can opt to have a reconditioned unit or an original part fitted.

I have been on the blower to my bank manager again today.
 
Back
Top