Tdi cruise control howto

[ewenmaclean]

Hello,

some folk asked me how I wired up my cruise control. I didn't use the proper switches and just used momentary switches I found from the usual suppliers. It's easy to wire this up if you've got a e-tdi setup. The things you will need to get are:

-- 2 pedal switch mounting brackets, for brake and clutch switches - available from rjes.
-- 2 push to make switches (i.e. releasing the pedal): vw part number 811907343B
-- 4 M12x1.5 bolts to hold the switches to the brackets
-- 4 no.8 self tapping screws to hold the brackets to the body
-- 2 push to make momentary switches (set and resume)
-- 1 non-momentary switch (for on/off of cruise operation) - e.g. an SPST 2 pin switch.
-- 1 rjes vss sensor for the tdi (8 pulse)

I assume a good earth and +12V supply are readily available.

The first thing to do is to wire up the pedal switches. Ignore the vacuum operation - this isn't necessary for the tdi.

For the brake pedal connect one pin to earth, and one to the white/yellow wire from the ECU which goes to pin number 20.

For the clutch pedal connect one pin to earth. and one to the white/red wire from the ECU which goes to pin number 17.

Now wire up the VSS. You will need to connect the 12V and earth as indicated by rjes, and the green signal wire connects to the blue/white wire going to pin 43 of the ECU.

Now connect up the cruise operation switches:

Connect the 12V to one (input) pin of the cruise on/off switch you have chosen, and connect the other (output) pin to the black wire going to pin 66 of the ECU, and also to pin 1 of the momentary switch you have chosen for "set" operation and pin 1 of the momentary switch you have chosen for "resume" operation.

For "Set" operation, connect pin 2 of the "set" momentary switch to the red wire going to pin 35 of the ECU.
For "Resume" operation, connect pin 2 to the "resume" momentary switch to the blue wire going to pin 34 of the ECU.

Here's a crap schematic to show what is described above:




Although not strictly necessary for cruise control. you need to wire up the black/red wire going to pin 44 to the feed for a brake light bulb. This is the wire that tells the ECU if a brake bulb is out. This needs to be calibrated with the brake switch you have just used for cruise control, otherwise you will get inconsistent signal DTCs for the brake lights. On mine as long as the lights come on very slightly after earth is broken from the footswitch (just installed) I don't get any faults. An alternative method here is to use a relay from the original brake switch but I prefer the extra footswitch method, especially as you already need one for the clutch pedal.

Finally you need to tell the ECU to activate cruise control in VCDS if it's not been activated on the donor car. This from the ross-tech site:

[Select]
[01 - Engine]
[Login - 11]
Enter 11463 to activate cruise control
[Do It!]

Here is a picture of my double momentary switch I chose set up:



This has been a bit rushed, but hopefully a bit helpful.

Ewen

[phil miller]

Ewen, after seeing your 25 last week (very good to meet you and your family) ive been thinking about all the little bits on mine i should be doing, and this ^^^^ is now top of my list, will be using this guide (maybe this weekend) to fit it on mine

Great write up

[ewenmaclean]

Cheers Phil,

great to meet you all too - good work on the van - great to see your excellent mounts for the LHS and for the potentiometer - hadn't seen that before, and great to see the van is already being used by the family for what it's supposed to be used for!

Ewen

[syncroandy]

Good write-up.

This info looks all good for 'early' 68-pin ECU's. For 'late' 68-pin ECU's (eg. as found in early 3B Passats, A4's maybe Sharan's) there are a couple of differences. The brake/clutch switches switch to 12V instead of ground, and there's an additional line to the ECU from the CCS switch which needs to be commoned onto one of the other ones if you want to use a T3 style CCS stalk. PM for info if you need it.

[ewenmaclean]

Thanks Andy,

good point - I knew that for the 80-pin ECUs but wasn't sure about the later 68 pin ones. I wonder if there's an easy way of telling from the software version? I know what I had is write for GG and GH ECUs, and I'm pretty sure it's ok for D* too - do you know if there's a good way of telling?

Ewen

[syncroandy]

I'd use the 'ATP' search in ETKA. That 'GG' code is a late Mk3 Golf, so it's 'early style' CCS wiring.