Cruise Control Not Working, Is It Even Installed 2009 Superb 2 1.9 Greenline

[CzechPassat]

Been working through the list of jobs on the tatty 1.9 Greenline I bought a month ago. 

 

Having fixed all the ABS issues I expected the Cruise Control to start working but no luck.

 

Another scan with VCDS and no errors showing anywhere (I've fixed everything). I'm not familiar with the Superb 2, I expected to find a module for Cruise Control, but none to be found. As it's fly by wire maybe it's in the Engine ECU? So far the only evidence that I might have Cruise Control is that there is a switch for it that doesn't do anything.

 

Any help appreciated.

[CzechPassat]

Many thanks to Breezy_Pete for decoding the VIN, The car does have Cruise Control

 

Now looking for a solution to get it working?

[Breezy_Pete]

"Steering column electronics control unit" appears to be what the cruise switch connects to first. Did your vcds scan include that unit?

[CzechPassat]

I have done a full scan and there are no errors anywhere. Haven't had a chance to look at it today so stay tuned and I'll dig a little deeper

[langers2k]

Might be worth posting your autoscan as it may give some pointers.

 

Otherwise, I'd probably try checking the measuring blocks relating to the CC switch position etc

[CzechPassat]

I’m a VCDS novice so working through measuring blocks may take a while.

[CzechPassat]

Well it didn't take as long as I thought.

 

I have the following codes:

 

01546 for left and left middle parking sensors, seems intermittent as they don't like getting wet.

00470 Company Comfort Databus In Single Wire. 011 Open Circuit-Intermittent

 

Checking the measuring blocks, the ones for the CC switch are all fine but it thinks the clutch pedal is permanently depressed, this would stop the CC engaging. 

 

I recently replaced the clutch Master Cylinder to cure the clutch pedal on the floor issue so not sure why this would have failed so quickly, seems unlikely it was a faulty unit.

 

[Breezy_Pete]

Did the replacement master cylinder come with a hall sensor clutch switch, or did that get transferred across from the old one?

[CzechPassat]

Came with a new switch. I still have the old master cylinder so could swap the switch or use it to test I suppose.

Not looking forward to having to replace the master cylinder again

[Breezy_Pete]

It must be detachable from the cylinder as the parts catalogue shows it as a separate part. So if the cylinder is working hydraulic-wise I'd hope you wouldn't have to remove/replace that part?

Any chance you just forgot to plug the connector back onto it? 

[Breezy_Pete]

Where did the replacement MC come from? Part number? 

[CzechPassat]

Borg and Beck, pic below

[Breezy_Pete]

Claims to be a replacement for the relevant genuine part numbers, but very cheap in comparison!

What caused you to replace it?

 

[nta16]

Borg & Beck are First Line, neither are always the finest parts available. - http://www.firstlineltd.com/

 

Sometimes they do the same part under both brands, not this time. - BCM123 - https://webcat.borgandbeck.com/PartDetails/BCM123/#partInfoBCM123

 

[J.R.]

1 hour ago, Breezy_Pete said:

Any chance you just forgot to plug the connector back onto it?

 

Every chance, the connector is a pig to remove and refit and breaks easily, mine is tywrapped together.

 

I paid £114 for a genuine VAG cylinder from TPS, then bu66ered that one up and fitted a couple of dirt cheap pattern parts at €18 each delivered, all had the reed switches integrated and all of them worked correctly.

[Breezy_Pete]

Hall sensor rather than reed switch, according to ETKA, at least on the OP's car. Potayto/ potarto though.

 

[CzechPassat]

I checked the plug yesterday and it seemed ok, but it is rather difficult to get to, so it’s possible, also possible the cable is damaged so further investigation required.

On the other hand I did eventually get the clutch bled properly and it’s been fine since.

[CzechPassat]

Any ideas how to check the switch either on or off the car as I can't make sense of it?

[Breezy_Pete]

Check under-bonnet fuse  #22 (5 Amp) before you do anything else. That seems to supply just the clutch switch/position sensor, at first glance.

 

If that's OK, you should get 12V at pin 5 of the connector at the pedal (red/blue wire), with ignition switched on with engine running.

 

With pedal not pushed, that should conduct straight through to the white/red wire on pin 2, and onwards to engine ECU pin 43 of the 94-way connector.

The brown wire on pin 1 needs to be connected to earth too, nothing will change if that's not intact.

When clutch pedal is pressed that 12V feed should be interrupted and no longer be seen on the white/red wire.

Edited 19 May, 2023 by Breezy_Pete
endless corrections

[CzechPassat]

I got as far as checking fuse 22 and it's all present and correct, I haven't got any further and am unlikely to have a chance to look at it for a couple of weeks as the clutch slave cylinder let go today. So I'm taking the opportunity to replace the clutch as the cover plate is causing a few issues.

I'll be back with an update in 2 weeks.

[CzechPassat]

Took me a little longer to replace the clutch than I expected, doing it on my back on the driveway. Replaced the slave cylinder (again) as the old heavy clutch had caused it to fail.

 

I've checked fuse 22 and pin 5 for 12v with the engine running, it's all present and correct. 

 

Next question. How do I check operation of the hall effect clutch switch? Ideally I'd like to check the spare one I removed from the car and fit that if it all checks out OK. There are just 3 pins on the switch numbered 1, 2 and 5 with 5 having the 12v feed.

 

Also a wiring diagram of the cruise system would be useful.

 

Many thanks

[Breezy_Pete]

I think testing off the car probably needs a small magnet to waft around near it, while having +12V on pin 5, the return/earth of that on pin 1, then measuring volts at pin 2 and expecting it to come and go as the magnet is/isn't adjacent.

Sort of as explained at the end of my post on May 19th above.

[CzechPassat]

Thanks Pete, makes sense now I’ve read it properly!

[CzechPassat]

Some progress made today.

 

I bench tested my old master cylinder switch with it fitted to the old master cylinder. All seems to work as it should producing a 12v trigger to the ECU.

 

I plugged it into the car and secured it under the bonnet with a couple of cable ties still attached to the old master cylinder. Went for a drive and for the first time I get a gear indicator on the dash, telling me what gear I'm in and an arrow indicating that I should change up/down. But the cruise still didn't work.

 

Working on the theory that the ECU needs to see the trigger appear when you change gear, rather than just be there all the time, I extended the loom into the car so that I could operate the old Master Cylinder and switch while driving. Success, the cruise engaged and disengaged exactly as expected.

 

Conclusion at this point is that either the new switch on the new master cylinder is faulty, so I will refit the old switch on the new master cylinder tomorrow in the hope that it works.

 

Such a pain getting to the bottom of the master cylinder to change the switch as there is so little space between the engine and bulkhead. I'm considering removing the bottom engine mount so that I can pull the engine forward and gain a few extra cm.

[J.R.]

On 14/06/2023 at 19:32, Breezy_Pete said:

I think testing off the car probably needs a small magnet to waft around near it, while having +12V on pin 5, the return/earth of that on pin 1, then measuring volts at pin 2 and expecting it to come and go as the magnet is/isn't adjacent.

Sort of as explained at the end of my post on May 19th above.

Sorry to hijack the thread but the OP had also asked a similar question about how the hall sensor works and how to test it.

 

As you know I have been faffing around with the (we think) hall effect sensor on my ABS wheel speed sensor, this only has 2 wires though, when disconnected it has 12v potential across the pair, what should the voltages be when the sensor is triggered and not triggered? ie with magnet in proximity and not.

 

I think I have found my answer and will send you a PM

Edited 17 June, 2023 by J.R.