Cruise control how to, AHU.

tongboy

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May 24, 2006
Location
Portland, OR
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91 Jetta TDI Swap, 97 M3 LS1 Swap
rsxsr said:
I am using the OE brake pedal switch from a 98 New Beetle on my vanagon. From memory. The description of the switch operation is correct, but I found the ECU needed to see the brake light bulbs to keep a code from showing up. The ECU gets a ground through the actual brake bulb filaments when off. When the pedal is depressed and the bulbs light, the ECU sees this change of state.

I am aware of this, because on the vanagon, I was using the original hydraulic pressure switches to activate the brake lights and the pedal switch to "talk" to the ecu. Not until I moved the brake lights onto the two way pedal switch did the code go away. I then worked on getting the cruise to work. My ECU was not coded for cruise control out of the box. It took two tries for the ECU to accept the cruise control.
i'm still using the hydraulic switch in my rabbit - as you said there is a normally open and normally closed switch in the modern brake switch, however I hard wired my clutch switch and my normally closed brake switch to ground so they don't affect the cruise system at all (prevent it from turning on or disable it if they are pressed) the only brake switch wiring I have is tied directly off the wiring that goes to the brake lights - the brake lights turn on and the cruise turns off, I get an improbable signal code for the brake light switch all the time but it works just fine.

and to the op - you have to address the brake and clutch switches that tell the ecu that the pedals are currently in the rest position or you'll never be able to turn the cruise on because the ecu believes that one of those pedals is down - it's a simple binary output in the ECU view, either the pedal switch is on or off and that will potentially prevent the cruise from firing up.

on the VSS wire - I fought with this a little as well. you have two options with it (I haven't tested the second but I'm told it'll work) output from the vss on the tranny to the cluster and then output from the cluster back to the ECU. the pinout of the cluster depends on which style you're using, i'm using a mk3 CE2 cluster and as I recall the vss output signal is block 2 pin 12 or 14, the wiring diagrams list the input wire to the ECU but it's tricky to run down exactly how they describe it. the other option is to bypass the cluster and run the vss signal directly to the ecu.

without a vag com it's going ot be really hard to diagnose that all your switches are working and your vss signal is being recieved by the ECU. i'd really recommend picking up a knockoff vag com cable on ebay for 20 bucks - i've been using mine without issue for a number of years now with great success
 

markward

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Loxahatchee, Florida
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82 Vanagon and 2011 JSW
Tongboy, I had mine wired as you did orginally. It was the improbable signal code that was driving me nuts. I wanted to run with no codes. Wiring in the factory two way brake pedal switch an bypassing the hydraulic brake switches cleared the error code. As best I could tell, it had to do with bulb filaments themselves. My only concern was that the new 2 way switch could not handle the load of the brake light bulbs. So far so good. If the load does damage the switch, I could add a relay to handle the load. My guess is some sort of bulb check is tied to the ECU. The switch is relatively cheap and a mounting bracket was easy to fabricate in the vanagon. I did not attempt the cruise hook up until I had all the codes solved.
 

Lone Ranger

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Winnipeg MB
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TDI Ranger
All this input is fantastic. And I can unbderstand the brake light switch and clutch switch having to be there, well especially the brake one, cause I did look at the wiring diagram and it is one normally closed and one normally open, so the one being normally closed has a 10 amp fuse going to the ECU so I can see my cruise not activating because of the switch not being present.

But the VSS to the ECU I don`t get, the jetta this TDI came out of had cruise and there is no wire i can find that is for VSS input to the ECU. I'm sure the can-bus handles speed signal to the ECU from the cluster.
 

tongboy

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May 24, 2006
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Portland, OR
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91 Jetta TDI Swap, 97 M3 LS1 Swap
Lone Ranger said:
All this input is fantastic. And I can unbderstand the brake light switch and clutch switch having to be there, well especially the brake one, cause I did look at the wiring diagram and it is one normally closed and one normally open, so the one being normally closed has a 10 amp fuse going to the ECU so I can see my cruise not activating because of the switch not being present.

But the VSS to the ECU I don`t get, the jetta this TDI came out of had cruise and there is no wire i can find that is for VSS input to the ECU. I'm sure the can-bus handles speed signal to the ECU from the cluster.
it's not labeled very clearly - I knew I was looking for one and I had to flip through all the wiring diagrams that involved the ECU until I found it but it's there, I guess i'd recommend starting with finding the pinout for your cluster and finding the ECU VSS output wire, for me it was I believe either on the green or black 10 pin connector that went to the interior, i'll check out in the garage
 

Lone Ranger

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why would their need to be a wire for VSS signal to ECU, if it needed it would'nt it already be there, cause obviosly the cruise worked in the jetta. I'm sure that the can-bus system would handle that. At least thats what my guys at my local VW dealer told me, then again they also said that it most likely needed the ABS computer for the cruise to activate, Can they be wrong with everything? hahah
 

tongboy

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91 Jetta TDI Swap, 97 M3 LS1 Swap
Lone Ranger said:
why would their need to be a wire for VSS signal to ECU, if it needed it would'nt it already be there, cause obviosly the cruise worked in the jetta. I'm sure that the can-bus system would handle that. At least thats what my guys at my local VW dealer told me, then again they also said that it most likely needed the ABS computer for the cruise to activate, Can they be wrong with everything? hahah
it should already have been there originally - in my case it's pin 51 on the 80 pin connector on the ECU, comes from wiring connection a27 which comes off the cluster VSS output and goes to the speed sensitive wipers & the ECU For cruise control. can bus could theoretically have handled the interaction but at least on the MY 99 & other mk4's it was still handled via signal wires, most likely to ease the ancillary systems like the radio/gps (europe only IIRC) & the wipers
 

mannytranny

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Oct 14, 2003
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CA
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02 Jetta (sold, such a great car) '16 Touareg
Would there be anything wrong with grounding the two brake signals (pin 20 and pin 44) as well as the clutch switch?

I don't need or want cruise control on this swap.

Also, my VSS has no home, but from what I've read that's only a problem if you have/want cruise.
 

Alchemist

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Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
This should do it for you.

ECU Pin 17 White/Red Clutch Switch F36
ECU Pin 20 White/Yellow Brake Switch F47
ECU Pin 44 Black/Red Brake Lights
Connect all of the above to ECU Pin 33 Brown/Blue Sensor Ground. This will simulate clutch engaged and brake released.
 

mannytranny

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CA
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02 Jetta (sold, such a great car) '16 Touareg
Ya, it is currently wired like this. The three pins are tied to the body/ground. I'll check continuity with pin 33 to be sure.

Thanks for the tip ;)
 

Rockwell

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Manchester, NH
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2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
Of the two brake inputs, one is normally open the other is normally closed and they toggle then the brake is pushed. I could be wrong, but I thought the ECM looked for that toggle to reduce stuttering when decelerating. I hope that's not the case, I don't want cruise either and that would reduce my wiring.
 

annieneff

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Jan 13, 2011
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Seattle
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1983.5 Westfalia tdi (afn), with flipped 5 speed V6 (dvz) transmission
If I need my own thread here don't be shy in telling me:

I have all the numbers working like they should. All the 0's, and 1's turn on and off as described above with each switch.
But I have no cruise...

I'm thinking it's the vss at this point, but how do I test that? Afn (very like an ahu) into a rabbit, full modern ahu instrument cluster.
When I drive it down the road, all the boxes in Chanel 6 in the engine section of vagcom do and show stuff-- the 1's, and 0's, and the number thing on the far right-- all of them work except the kph box on the far left doesn't register anything while I'm moving. Does that mean it's not getting the vss signal? I verified the switch is hooked up on the top of the transmission.

Any suggestions/ideas of where to look or what to do next will be appreciated!

Andrew
 

Alchemist

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Nov 3, 2007
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Lethbridge, Alberta
TDI
'04 ALH Golf
My notes say VSS connects to ECU Pin43 Blue/White from Instrument Cluster Pin 7. I think there should be a reference to which connector on the cluster, but I don't have that close at hand.

HTH
 

annieneff

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Jan 13, 2011
Location
Seattle
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1983.5 Westfalia tdi (afn), with flipped 5 speed V6 (dvz) transmission
I appreciate the idea, and I'll check that out.

A little more information; my wiring harness is very near complete. I didn't take it apart and do the whole labeling thing that other people do. I just stuck the whole thing in there and hooked up what I needed to, to make it run, and for everything to work... So I think the vss should just be hooked up and working. Especially since my speedo, tach, and gas gauge work just like they should.

But clearly I'm missing something...!

Edit: I connected (jumper wire) the violet/white wire off of the instrument cluster, to the white/blue wire that comes from the vss, and connects to the fuse/relay panel on plug G1/11, and it made the kph box register in channel 6, and the cruise control work! Victory and awesomeness are mine :)... And functioning cruise control. Thanks all!

Andrew

Ps. If anyone ever has a cruise control question that isn't covered here, feel free to contact me. I started out knowing Ø. And I think I know very little crevice and obscurity of this system now. I'd be more than happy to share what I know any time!
 
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jackbombay

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Mar 12, 2002
Location
Diesel knows best
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A4 Jetta
Good to hear you got it working, the ECU controlled CC is awesome.

Its been several years since I put this thread together, so its a ll a bit foggy for me now, but its good to hear it was of some use to you :)
 

G60ING

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Aug 5, 2001
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MD
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No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta

annieneff

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Jan 13, 2011
Location
Seattle
TDI
1983.5 Westfalia tdi (afn), with flipped 5 speed V6 (dvz) transmission
What made you put that in your signature? Funny and weird.
 

G60ING

Top Post Dawg
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Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
What made you put that in your signature? Funny and weird.
People are always asking me how to do this or that and its been 7+ years since I did my last swap.
 

IltisTDI

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Jul 27, 2015
Location
Toronto
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Iltis/AHU
I am currently working on a swap in a former military vehicle (little truck/jeep-like thing called an Iltis). I would like to have a functioning cruise control but in pondering the prospect, I came up with another idea which I think would be even cooler- crawl control.

Here's the idea: rather than running a VSS which I cannot fit (easily) to this transmission, what about mounting a hall effect sensor and couple magnets to the crankshaft or camshaft to provide a simulated VSS. I know most cruise control systems will only function above 60km/hr so this may need multiple magnets (trigger points) so that at a high idle, the ECU would see a simulated VSS greater than 60km/hr. This would allow you to set cruse control based on engine RPM rather than vehicle speed allowing you to put the vehicle in cross-country gear (super low gear), set "cruise" at a high idle and put along at a walking pace to crawl over rocks and obstacles almost like an auto-idle feature.

Here are the unknowns:
1) What sort of signal does the VSS produce? is it just an inductive pulse, or a switched 12V+ signal?
2) What speeds will the cruise control operate at, more specifically based on (1), what frequencies of pulses will it operate at. (does it have an upper limit or will it maintain throttle control at a perceived 500km/hr VSS?)
3) I'm a lazy guy and don't like doing more fabrication and wiring than needed, so what sort of signal does the tach signal wire to the cluster generate? Can I just wire this to the VSS signal wire to feed the ECU its own tach signal for reference? What about the crank position sensor signal?

I no longer have the VSS from this vehicle or an oscilloscope so I haven't been able to conduct my own testing.
 

G60ING

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Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
I can't help you but the Iltis is an awesome swap, I think I recall somebody posting pictures on the vortex of their AHU TDI swap.
 

Hasenwerk

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Quesnel, BC
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1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
I sell two products at http://www.fastforward.ca you might be interested in:

Speedpuls CV
This is a VSS that reads the bolts on the CV joint as they go by (or any other but of rotating metal) so six pulses per wheel revolution on your Iltis. No magnets required. Just 12V and Ground and yes the signal is compatible with the TDI ECU!

Speedpuls Tachotronic
This will take the signal from the Speedpuls CV and calibrate so that the TDI's ECU will report the true speed of the vehicle. It will multiply the input signal from 0.25x to 10x with 975 steps in between. Technically with this you could have cruise control at almost any speed. I am not sure the real minimum speed the ECU will allow cruise control to operate, but say it's 50km/h - you could set the multiplication so that real world 50km/h is reported to the ECU as 100km/h or 150km/h so that in the real world you could set the cruise control as low as 25km/h or 18km/h for some nice crawling capabilities! If you go this approach I would get some chip tuning done so that the speed limiter is removed from the ECU - most are set at 250km/h.

Way back in 1998 I imported three Volkswagen Iltis to Canada from the German military - I do miss those vehicles!
 

IltisTDI

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Jul 27, 2015
Location
Toronto
TDI
Iltis/AHU
Thanks for the input David, I'll definitely consider your suggestions. I think my solution (which may involve your Speedpuls CV) is going to include two sensors with a two-position switch to select one or the other. One will read a relatively typical VS signal for use with cruise control while the other will read a signal from the engine crankshaft at a higher rate for "crawl" control. This way I can maintain an appropriate signal resolution at the flick of a switch depending on what I'm doing at the time without having to remove speed limiters or modify the signal.
 

clyde

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confluence, Snake/Clearwater
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1998 Jetta, 1959 DeSoto with leopard-skin seat covers
Before you "flip the crawl/cruise" control switch you might want to turn the system off…or suddenly vault from 2 mph to 20 mph
 

Hasenwerk

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1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
In my off-road experience with the Volkswagen Iltis / Vanagon Syncro / LT 4x4, I don't think when I am crawling along I would want to use cruise control as I am always varying my speed to a degree. You will find that in 1st or 2nd gear at idle, the engine won't want to stall unless you've just hit a major obstacle and then I think I would want to be in control and not the CCS. Less is more, complicated things fail in extraordinary ways, keep it simple... you get my idea!
 

vtpsd

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Aug 15, 2013
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Vermont
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03 jsw TDI, audi 90 AHU swap
I'm going to bump this up. I just got through making cruise work on my audi 90 with an AHU swap, and thought I would add my two cents. This whole topic was helpful. I am basically saying the same thing as the original post, but maybe with some more detail.

I was able to make the cruise function 100% using the factory audi stalk switches and pedal switches.

The stalk switch on my car did nothing when I tried to pin it out. It has 12v going in, but nothing coming out of any of the other pins. I took it apart and cleaned all the contacts and then was able to get 12v out of 3 of the pins. (cruise on, cruise set, and cruise resume all gave out 12v when pushed).

dirty pins with 30 years of corrosion and dried grease:


cleaned up:


The factory clutch on the audi has a switch that is connected when the clutch is up and broken when the clutch is down

The brake has two switches.

-One switch carries constant 12v and is open when the pedal is up. It closes when the pedal is pushed and the output of this switch goes to the brake lights.

-The other switch on the brake is closed when the pedal is up and broken when the pedal is pushed. I think this was only used for the audi cruise control module, which I no longer use.

Since I was no longer using the audi cruise control module. I totally cut the wires that were on the clutch switch and the second brake switch. I grounded one pin on each of these switches.

-The output side of the clutch switch went to pin 17 on the ecu. This pin is now grounded when the clutch pedal is up and open when the pedal is pushed.

-The output side of the second brake switch went to pin 20 on the ecu. This switch is grounded when the brake is up and open when the brake is pushed.

-Pin 44 on the ecu went to the brake light side of the first brake switch. In other words, I tapped into the brake light input circuit that is provided with 12v when the pedal is pressed. This circuit is grounded when the pedal is up through the brake light filaments and is brought to about 12v when the pedel is pushed. So the ECU sees this pin as a ground when the brakes are up and 12v when the brakes are down.

I was about to try and graft a mk4 brake pedal switch to my car to make this work, but I gave it a second look and was able to make it work with the factory switches. I have noticed several other old german cars have a similar switch setup, so this might be helpful for someone else.

Its one of those things that is pretty confusing when you are just reading other peoples forum posts. But when you figure it out, then it is really obvious.

I found the VAGCOM outputs on the original post were accurate to my car when I got the switches working right.

My mk4 ALH gas pedal now behaves much better with my switches wired in. With them unhooked the pedal has some strange behavior. Much better now.
 
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1.9ZOOK

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Dec 13, 2015
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Downstream of a Volcano
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ALH Samurai
My mk4 ALH gas pedal now behaves much better with my switches wired in. With them unhooked the pedal has some strange behavior. Much better now.
This is good to know,I have been doing much searching regarding CC into
my Samurai build,I have purchased the two brake switches(one of which is vacuum assisted)and the clutch switch which is also vacuum assisted.So I
assume I will need to get hold of a vacuum pump,correct?
 

vtpsd

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Joined
Aug 15, 2013
Location
Vermont
TDI
03 jsw TDI, audi 90 AHU swap
This is good to know,I have been doing much searching regarding CC into
my Samurai build,I have purchased the two brake switches(one of which is vacuum assisted)and the clutch switch which is also vacuum assisted.So I
assume I will need to get hold of a vacuum pump,correct?
No need for any vacuum switches or pumps with the TDI cruise control. The ECU does it all internally with a few electrical only inputs from the pedals and the stalk. The throttle pedal is not actuated like in a drive by cable gas car.

My audi also had vacuum switches with the electronics, but I totally removed all the vacuum stuff since I am letting the TDI ecu run the cruise 100%.
 

ToddA1

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Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Both of my B4s cruise works occasionally. I'm going to need to disassemble the switches and clean them out.


My mk4 ALH gas pedal now behaves much better with my switches wired in. With them unhooked the pedal has some strange behavior. Much better now.
You're using a "gas" pedal, now? I remember you saying you were going to get a diesel pedal.

-Todd
 
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