EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
  
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| Yawn, Cruise fault thread |
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Sorry guys, I know there are many faults on cruise, I cant find one that relates to my issues. Everything on mine appears to work, no error messages, cruise speed sets fine, but when you take your foot off the throttle, the car just slows.
No matter what you set it at nothing happens.
There have been a couple of times I thought that it was slowing less than others but cant be sure.
Any idea where to start looking? Or am I being a fud and have set it wrong?
Any hints appreciated.
D4, TDV6 XS 2010 MY
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 16th Aug 2019 11:19 am |
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Narpy
Member Since: 18 Jul 2011
Location: Stockport
Posts: 7830
 
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Are you getting a dashboard light when you press the cruise button? Mods:
Front Fogs + Halos
FBH Remote Control
The 1st Ever RRS Modded Grill
Garmin Nuvi + D4 Surround + Reversing Camera.
D4 Steering Wheel.
Rear Boot Spoiler.
Twin Brake Lights.
Wing Mirror Indicator Repeaters.
Long Roof Rails
Make your own Narpy grill thread
I'm not scared, I'm outta here.
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| 16th Aug 2019 12:41 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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From memory, the little speedo/clock symbol comes up and the central display says cruise set to X speed.
As soon as you touch the brakes or throttle, it goes off.
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| 16th Aug 2019 3:52 pm |
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Narpy
Member Since: 18 Jul 2011
Location: Stockport
Posts: 7830
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It should go off if you touch the brakes, that's normal.
Throttle however, it should stay on. Mods:
Front Fogs + Halos
FBH Remote Control
The 1st Ever RRS Modded Grill
Garmin Nuvi + D4 Surround + Reversing Camera.
D4 Steering Wheel.
Rear Boot Spoiler.
Twin Brake Lights.
Wing Mirror Indicator Repeaters.
Long Roof Rails
Make your own Narpy grill thread
I'm not scared, I'm outta here.
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| 16th Aug 2019 3:58 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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Basically, theres no attempt to maintain the speed of the car, it just drops off straight away. It says speed set to 70mph but the second you take your foot off the throttle, the car starts slowing and the engine revs drop.
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| 16th Aug 2019 4:28 pm |
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Narpy
Member Since: 18 Jul 2011
Location: Stockport
Posts: 7830
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Does the cruise light go out when you take your foot off? Mods:
Front Fogs + Halos
FBH Remote Control
The 1st Ever RRS Modded Grill
Garmin Nuvi + D4 Surround + Reversing Camera.
D4 Steering Wheel.
Rear Boot Spoiler.
Twin Brake Lights.
Wing Mirror Indicator Repeaters.
Long Roof Rails
Make your own Narpy grill thread
I'm not scared, I'm outta here.
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| 16th Aug 2019 4:35 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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No, it behaves as if its holding speed.
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| 16th Aug 2019 4:45 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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Ive been out in the car to test this and heres what happens
Press Set and green clock icon appears. Set speed displays correctly.
Take foot off throttle car immediately slows. No change on dash.
Press the plus/set button, to try to add to the speed, the set speed goes up. Car does not speed up as if throttle not being actuated.
Eventually have to press the throttle pedal and the message changes to cruise cancelled or similar.
Puzzled
Any help would be appreciated. Does this sound familiar to anyone?
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| 19th Aug 2019 7:12 pm |
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Famousfive
Member Since: 12 Aug 2014
Location: Southampton
Posts: 1832
 
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Not heard of this before, especially as the control unit is registering the speed being set on the cluster.
No fault codes from IID or similar either?
Std fault finding issues:
1) rotary coupling
2) Steering wheel switches
3) Check the continuity on steering wheel loom
4) check connections on the pcm module behind the battery
5) brake pedal switch, check rear brake lights are working
IIRC the cruise is controlled by a vacuum and it sounds like its that what is failing ... but I’m no mechanic and don’t know how you diagnose if it was, sorry.
Hopefully an expert will be along shortly 
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| 19th Aug 2019 7:52 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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Quote:
Not heard of this before, especially as the control unit is registering the speed being set on the cluster.
No fault codes from IID or similar either?
Std fault finding issues:
1) rotary coupling
2) Steering wheel switches
3) Check the continuity on steering wheel loom
4) check connections on the pcm module behind the battery
5) brake pedal switch, check rear brake lights are working
IIRC the cruise is controlled by a vacuum and it sounds like its that what is failing ... but I’m no mechanic and don’t know how you diagnose if it was, sorry.
Hopefully an expert will be along shortly Thumbs Up
OK
Rotary coupling
I dont have any issues with anything else on the rotary coupling, and normally turning the wheel to a different position would allow the fault to be temporarily cured, but to no avail. Could be but not looking likely as the indications all look OK. Not discounting this yet.
Steering Wheel switches
Everything works as expected
Steering wheel loom
Will need to research this one. Thanks.
PCM Module
Need to check this one, thanks.
Rear lights/Brake switch
I have a new one to fit which I hope to do this evening if my kids let me have time. Brake lights work fine but are very very sensitive. I've a hairs touch to activate the brake lights. I have to push the pedal a fair bit further to move the handbrake as well. Looking into this one.
IIRC
I don't have this, I have the iCarsoft LRv2, the widescreen fella.
What systems would I check to diagnose this? There are so many!!
Vacuum
This could be the problem as the brake pedal responds well when I'm driving and after stopping the engine and restarting a few minutes later the brake pedal is brick hard like the vacuum has leaked away. I will need to dig into this one also. Thanks.
Cheers
Warren
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| 20th Aug 2019 2:56 pm |
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swansty
Member Since: 21 Sep 2008
Location: Northern Ireland
Posts: 942
 
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I had the hard brake pedal symptom although it took a few hours before the pedal was hard - new servo cured that
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| 21st Aug 2019 8:54 am |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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Sounds like it may be vacuum or servo related then?
Thanks
Warren
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| 21st Aug 2019 1:07 pm |
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Flack
Member Since: 06 Sep 2006
Location: Preston Lancashire
Posts: 6308
 
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Has the car had the belts done?, there are some vac pipes at the rear of the engine make sure these are still intact.
They might have disturbed them if the rear belts been changed.
Flack
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| 21st Aug 2019 1:32 pm |
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EdinWarren
Member Since: 15 Apr 2019
Location: Edinburgh
Posts: 32
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Supposed to have been done before I got the car so possibly. Thanks.
There is what looks like a vac pipe with a plug sticking up next to the nearside headlight. Its just flapping about. It has a wee cap on the end with a cross it.
Ill be checking the vac lines when it stops raining. Whats the access like at the back of the engine?
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| 21st Aug 2019 3:22 pm |
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Flack
Member Since: 06 Sep 2006
Location: Preston Lancashire
Posts: 6308
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Quote:Whats the access like at the back of the engine?
Bad , there are also a some vac pipes at the front of the engine, if you look on the top right hand facing the engine, you will see a bracket with a valve, it has a couple of pipes and plug attached to it, check these out. They go across the front of the engine and branch off to the rear and down the drivers side to the secondary turbo, all these get moved when belts are done.
Flack
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| 21st Aug 2019 3:54 pm |
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