Cruise Control just stopped working

[OldAudiA4]

On a long trip, just stopped working. Any ideas. Checked the fuse, all good.

[OverSpun]

The stalk will likely need to be replaced. I had that issue and it resolved the issue.

[OldAudiA4]

From looking at this photo:



It seems as though the cruise control stalk has bushes in it? Is that right, if so, they are a wearable item like the air con bushes (of which I just repaired). Is that right?

[b6Hate4]

My cruise control stopped working for the longest time, at one point I had swapped the ECU for a replacement with a big turbo file and bam my Cruise control was back.

Super odd, but just some info incase the stalk turns out to be OK.

[Avant Nate]

Could be the cruise control module, was for me.
http://www.audizine.com/forum/showth...65#post4911265

[OldAudiA4]

From reading it can either be stalk, control module, or possibly actuator. Think I'll test the actuator tomorrow. Don't know if it makes a difference to diagnosing my problem but the whole time I've had my cruise control, I have to set it at about 5km/h over what I want it, then the car slows down about 10km/h, then goes up about 5km/h to get to the speed I want. Could that indicate actuator on the way out which has finally died? I know it's probably sitting somewhere simple but where is the actuator in the engine bay. Mine is an AEB.

[Mattr567]

My cruise control stopped working for the longest time, at one point I had swapped the ECU for a replacement with a big turbo file and bam my Cruise control was back.

Super odd, but just some info incase the stalk turns out to be OK.

Similar story. When I swapped for a chipped ecu (557P to 557N) my cruise control stopped working. Might be bad timing but I haven't switched back to check if it works again.

[mfdk]

My cruise control has never work since i bought the car, i never really bothered with it, but i when slide the button between cruise and reset nothing happens at all no lights on the dash.

2001 v6 2.8

[OverSpun]

From reading it can either be stalk, control module, or possibly actuator. Think I'll test the actuator tomorrow. Don't know if it makes a difference to diagnosing my problem but the whole time I've had my cruise control, I have to set it at about 5km/h over what I want it, then the car slows down about 10km/h, then goes up about 5km/h to get to the speed I want. Could that indicate actuator on the way out which has finally died? I know it's probably sitting somewhere simple but where is the actuator in the engine bay. Mine is an AEB.

My set button was causing the issue or something related with it. A new stalk fixed it.

[walky_talky20]

Of high importance to this discussion is which type of cruise control you have. The B5 has 2 entirely different systems based on model year (throttle type).

99.5 and earlier: Cable Throttle with a Vacuum based cruise system and a separate cruise control "module". The module, stalk, and actuator diaphragm are all high failure rate items. VCDS is not useful to diagnose this system.

2000 and newer: Drive-By-Wire throttle. Cruise control is literally just a software program in the ECU and there are very few moving parts (stalk, brake/clutch switches, that's pretty much it). The ON/OFF and SET button in particular are high failure rate items. You can use VCDS Measuring Blocks to check the operation of each individual cruise button on the stalk and see what's up.

[OldAudiA4]

Of high importance to this discussion is which type of cruise control you have. The B5 has 2 entirely different systems based on model year (throttle type).

99.5 and earlier: Cable Throttle with a Vacuum based cruise system and a separate cruise control "module". The module, stalk, and actuator diaphragm are all high failure rate items. VCDS is not useful to diagnose this system.

2000 and newer: Drive-By-Wire throttle. Cruise control is literally just a software program in the ECU and there are very few moving parts (stalk, brake/clutch switches, that's pretty much it). The ON/OFF and SET button in particular are high failure rate items. You can use VCDS Measuring Blocks to check the operation of each individual cruise button on the stalk and see what's up.

From reading around the forum on cruise control, you seem to be the cruise control guru walky_talky. Mine is a '98 model. I removed the switch cap on the stalk and sprayed contact cleaner in there to no avail. I've seen the actuator pic you posted somewhere else on ecs and seen the youtube vid you posted on how to test it, but I cannot find it in the engine bay

[Bordom]

From reading around the forum on cruise control, you seem to be the cruise control guru walky_talky. Mine is a '98 model. I removed the switch cap on the stalk and sprayed contact cleaner in there to no avail. I've seen the actuator pic you posted somewhere else on ecs and seen the youtube vid you posted on how to test it, but I cannot find it in the engine bay

If you have a 98, then it is more than likely the cruise control module behind the glove box.

When I owned my 96, cruise control never worked until I found a repair DIY for it. You need to reflow the solder joints around the capacitors and then it should work again.

I'll try to find a link for you.

EDIT: Here it is: http://redirect.viglink.com/?format=...Bpostcount%3D3
Sent from my SM-G935W8 using Tapatalk

[seanf86]

I tried re flowing the module multiple times and it would work for a few hours than quit. For some reason the part in the USA is like $500 I paid full retail last year at my dealer and it was $244 CAD out the door and my cruise works flawlessly.

Sent from my BLU STUDIO SELFIE 2 using Tapatalk

[Avant Nate]

From reading around the forum on cruise control, you seem to be the cruise control guru walky_talky. Mine is a '98 model. I removed the switch cap on the stalk and sprayed contact cleaner in there to no avail. I've seen the actuator pic you posted somewhere else on ecs and seen the youtube vid you posted on how to test it, but I cannot find it in the engine bay

The actuator is hanging off the throttle body, there is a a little rod which attaches it to the actuator. This is the closet thing I could find:

[OldAudiA4]

The actuator is hanging off the throttle body, there is a a little rod which attaches it to the actuator. This is the closet thing I could find:

I'm sure it's there, but I cannot find it on my AEB...

- - - Updated - - -

Of high importance to this discussion is which type of cruise control you have. The B5 has 2 entirely different systems based on model year (throttle type).

99.5 and earlier: Cable Throttle with a Vacuum based cruise system and a separate cruise control "module". The module, stalk, and actuator diaphragm are all high failure rate items. VCDS is not useful to diagnose this system.

2000 and newer: Drive-By-Wire throttle. Cruise control is literally just a software program in the ECU and there are very few moving parts (stalk, brake/clutch switches, that's pretty much it). The ON/OFF and SET button in particular are high failure rate items. You can use VCDS Measuring Blocks to check the operation of each individual cruise button on the stalk and see what's up.

Mine is a '98. Would you suggest to tackle the module, stalk or actuator first?

[elduderino200]

Just yesterday I did the solder-module repair as well as the press-the-stalk-buttons-100-times repair and now I have cruise again!

Not sure which did it, if not both, but for a free fix, the price was right.

Mine is a '98. Would you suggest to tackle the module, stalk or actuator first?

I would do this (if you haven't): check the fuses, that's free and takes 30 seconds. Then locate and check the actuator, that takes a minute or two, all you have to do is take the vaccuum hose off, press up (gingerly) on the diaphram, hold your finger over the vaccuum port you just removed, then see if it holds a vaccuum. If it drops down with your finger making a good seal, it's the actuator. After that, click the CC buttons on the stalk 100 times in quick succession, it could be a buildup of oxidized crap. Both the 'set' button on the end and the 3-way on/off/resume switch.
Those fixes should all be free and take 10 minutes total. After that, do the solder fix on the module. Hopefully you can borrow a soldering iron and a bit of solder from someone who has one, or give them a 6-pack to do it.

Fortunately for me I didn't need to go further than that because I did all those, took it out and tested it, and it started working. If those don't work, I understand the vehicle speed sensor is a possibility? Frankly I'm not sure about that. It's also possible your stalk is TOO cruddy or your module is messed up beyond this simple repair.

[OldAudiA4]

I think I worked out why I can't find the actuator. There are two lines coming from the throttle, one I assume is the accelerator input, the other goes to a box marked 'cruise control' with a wiring loom coming out the other end of the box. My car is a '98 model but does this mean I have the other cruise system walky_talky20 mentioned earlier in this thread? I've attached photos of the box.

[seanf86]

I think I worked out why I can't find the actuator. There are two lines coming from the throttle, one I assume is the accelerator input, the other goes to a box marked 'cruise control' with a wiring loom coming out the other end of the box. My car is a '98 model but does this mean I have the other cruise system walky_talky20 mentioned earlier in this thread? I've attached photos of the box.

that looks like someone has installed an aftermarket cruise control in your car, probably because the oem one broke.

[OldAudiA4]

I think you're right. Looking closer at the bracket, it looks custom made. Soon I have to install a radio aerial and gps antenna which will involve removing the glove box, so I'll have a look then to see if the cruise control unit is there and then try and work out the best way to get it fixed. Will probably have to try and work out if it's the stalk, the mystery box, or the clutch or brake switch.

[walky_talky20]

All of that stuff is reasonably easy to test from the OEM cruise control module location with a multi-meter, or even just a test light.

[OldAudiA4]

Thanks for the response. So I was driving on the highway today and just thought I'd give it a try and it started working again. The only thing I had done was spray the stalk switches with contact cleaner and moved the switches 100 times each, but when I tested it straight after doing that it didn't work. So I'm guessing the stalk is a bit twitchy or the contact cleaner hadn't dried internally?

[maxiz1]

Thanks for the response. So I was driving on the highway today and just thought I'd give it a try and it started working again. The only thing I had done was spray the stalk switches with contact cleaner and moved the switches 100 times each, but when I tested it straight after doing that it didn't work. So I'm guessing the stalk is a bit twitchy or the contact cleaner hadn't dried internally?

Most of the stalk buttons suffer from oxidization of the internal circuit board copper contacts. Do not attempt to buy a used one as you would suffer from the same problem. Contact cleaner will not cut it. Split open the stalk and sand down the copper using fine sand paper.

However, check the contact operation using VCDS or multimeter.

[OldAudiA4]

Most of the stalk buttons suffer from oxidization of the internal circuit board copper contacts. Do not attempt to buy a used one as you would suffer from the same problem. Contact cleaner will not cut it. Split open the stalk and sand down the copper using fine sand paper.

However, check the contact operation using VCDS or multimeter.

Cruising down the highway, just stopped turning on when required, worked for a good few hours. I'm guessing it might be the stalk? Is there much involved in splitting open the stalk without braking it?

[maxiz1]

Guide is in this link:
http://forums.quattroworld.com/s4s6/threads/1634.phtml

Not difficult apart from removing the steering wheel. Use gentle force with a plastic pry tool and watch out for the small springs.

[OldAudiA4]

Guide is in this link:
http://forums.quattroworld.com/s4s6/threads/1634.phtml

Not difficult apart from removing the steering wheel. Use gentle force with a plastic pry tool and watch out for the small springs.

That's a pretty comprehensive write up! thanks.

If I was looking to replace the stalk with a new oem one, does anyone know if the 99+ stalks will work on a pre 99 model?

[OldAudiA4]

In the end, I ended up finding the set wire from my aftermarket cruise control and wiring a new switch into the dash. So looks like the problem was the set switch in the stalk. When I tested the set switch in the stalk with a multimeter, it gave intermittent results.

[OldAudiA4]

Just an update. After a long trip, stopped working again towards the end. Checked the switch I put in, all good. Checked the +12v wire and the set switch still operating ok, all good. Checked the brake / clutch switches having an input into the cruise control, all good.... couldn't work it out.

I happened to notice while I was testing the wiring that I could hear a noise under the bonnet, similar to a solenoid moving. I popped the bonnet and had a look at the throttle cable and associated assembly coming from the cruise. I noticed that the throttle plate when I first moved it was a little 'sticky'. I moved it up and down a few times, then tested it, and it started working again! I lubbed it up a little to try and ensure it doesn't get stuck again.

I've had an incident before in a BMW where I drove through small flood water and the accelerator stopped working. Turned out that the throttle plate was stuck in the closed position. I inferenced that some humidity got into the inlet and closed it stuck. Same result there, lubed it up and all good.

[OldAudiA4]

A further update.

The cruise control seems to work now but on long journeys it will eventually stop after I try to engage it after it being disengaged (such as when pressing the brake).

When the car then sits for a while and you turn it on, I can hear the solenoid making a noise (like re-setting).

Any ideas how to fix it?

[OldAudiA4]

A further update....

so I opened the aftermarket cruise control unit box up, it's a Rostra brand one. Sort of figured out how it basically works. Tried lubricating it but then realised that the servo inside the cruise control module box is pretty powerful and a lack of lubrication wasn't the issue. From reading online, an aftermarket Rostra cruise control fitted on a motorbike and having similar problems, someone suggested that it might be interference, like a type of electrical interference, and they suggested to either put a capacitor between positive and negative going into the control unit module or use a car audio electrical noise filter. So I did that and it appears to be working again, but I'll have to see how long for!

[OldAudiA4]

So it worked well for about an hour then the same problem. It's like the servo inside the box just turns to custard. Not sure what's causing it. Now when I turn the car on, I can hear the servo/solenoid moving but it still doesn't work. I'm going to open it back up and fiddle with the settings (via dip switches) on the circuit board. Some settings I don't understand which I can adjust on my cruise control:

Pulses Per Mile - 2000, 4000, 5000, 8000.
Control Switch - Open Circuit Control Switch, Closed Circuit Control Switch.

Also, the dip switch currently has it set to 5 or 6 cylinders instead of 3 or 4 cylinders. I left this setting as it was, as the cruise control worked when it was working, but I might change it to 3 or 4 and see if it solves the ongoing problem.

Anyone got any ideas on the correct settings for Pulses Per Mile and/or Control Switch as outlined above.

[OldAudiA4]

So after reading online and looking at Rostra manuals, one manual mentioned that the blue wire which connects to the tachometer is not used on a manual car, if you have a clutch switch installed on the clutch pedal. I wasn't the original installer of this aftermarket system on my car, but when previously testing, I worked out that there appeared to be a switch installed on the clutch pedal. The Rostra manual mentioned that if a clutch switch is installed, the blue wire should be grounded to prevent "trashy" signals being received. Testing the voltage of the blue wire with a micrometer displayed variable voltages going down (sort of between 6v going down to 3v). This would explain why the cruise control stopped sometimes but not others. I grounded the blue wire to a constant 12v grounding. Test drove it again and it's all working...for now. I'll have to see how it goes on my next long drive.

In the process of trying to fix this, I lubricated the shaft that carries the electromagnet with WD-40. It appears that this also lubricated the drive shaft out of the electric engine connecting to a rubber belt, which connects to the gear pulley which moves the electromagnet. This has caused the belt to slip! I degreased it but it still slipped. I shoved a piece of dishwashing sponge in their to try and guide it and stop it from slipping off the engine shaft. I moved the gear and belt backwards and forwards a number of times and it appeared to stay. A pretty dodgy fix to getting the belt to stay on I suppose but I couldn't think of any other way of keeping it on there.