Stop Start error & ACC not working

[davegsm82]

Hi Dave, sorry about the (very) late reply!

thanks for mentioning this, how hard would this be for someone with virtually no experience or skill set to do (me) . I really do want this to work but just keep putting it off. If it’s possible would I just be able to get this wiring sorted, how do I check if the radar itself is good? - I may have a stab at having a look at this canbus wiring but how would I check if it’s working or needs repairing. I also have the domed radar too. Lastly how much would this cost for me to either do myself or pay someone to do??
Once again thanks for your post

Hi Isacheema,

Ok. So I've been on a bit of a journey with this over the last couple of weeks.

Short story of it is, the radar itself was knackered. Long story is, I'd been through all the wiring, checked the power supply to it, checked the grounds etc, I made myself a canbus interface and found that the radar wasn't communicating at all sometimes. You'd turn on the ignition and nothing, which is when you get the Stop-Start error.

But. I'm an electronics engineer so once I'd exhausted all other options, I ripped the Radar out and dug into it, to see if I could repair it.

In my case, I've been able to actually repair the radar and have been considering the possibility of offering a postal repair service for them, because the alternative is extremely expensive. Working domed front radars are few and far between on the used market, £200-300 and after that you have to have component protection removed (£100-200) and potentially have ADIS calibration performed which seems to be quite variable but VW/Audi charge something like £500.

The problem with these radars is water ingress, the rubber seal around the back of the units fails because of aluminium corrosion, then they fill up with water and either the connector on the bottom falls apart or you get lucky and one of the components on the board blows, saving the rest of the unit. I've 'autopsied' 3 units in total and they all feature the same type of water ingress. I dare say that EVERY one of these radars will fail this way eventually.

You can see a picture of the inside of my radar on this page; https://golfmk7.com/forums/index.ph...-when-swapping-parts-info.386155/post-7674014

The repair process is very labour intensive unfortunately, it has to be stripped, every one of the corroded screws holding the back cover on will snap, The electronics then have to be extracted and repaired if possible. If it's viable then the snapped screw studs have to be extracted by either welding on nuts or drilling them out if that fails. The case has to then be shot-blasted and the whole thing reassbled with a new rubber seal etc, all of this takes hours and hours.

Upshot is, if you repair your old radar then you should be able to just clip it back into place and conserve your original calibration. Only downside is you can't guarantee your Radar will be repairable :-/

 

[isacheema]

Hi Isacheema,

Ok. So I've been on a bit of a journey with this over the last couple of weeks.

Short story of it is, the radar itself was knackered. Long story is, I'd been through all the wiring, checked the power supply to it, checked the grounds etc, I made myself a canbus interface and found that the radar wasn't communicating at all sometimes. You'd turn on the ignition and nothing, which is when you get the Stop-Start error.

But. I'm an electronics engineer so once I'd exhausted all other options, I ripped the Radar out and dug into it, to see if I could repair it.

In my case, I've been able to actually repair the radar and have been considering the possibility of offering a postal repair service for them, because the alternative is extremely expensive. Working domed front radars are few and far between on the used market, £200-300 and after that you have to have component protection removed (£100-200) and potentially have ADIS calibration performed which seems to be quite variable but VW/Audi charge something like £500.

The problem with these radars is water ingress, the rubber seal around the back of the units fails because of aluminium corrosion, then they fill up with water and either the connector on the bottom falls apart or you get lucky and one of the components on the board blows, saving the rest of the unit. I've 'autopsied' 3 units in total and they all feature the same type of water ingress. I dare say that EVERY one of these radars will fail this way eventually.

You can see a picture of the inside of my radar on this page; https://golfmk7.com/forums/index.ph...-when-swapping-parts-info.386155/post-7674014

The repair process is very labour intensive unfortunately, it has to be stripped, every one of the corroded screws holding the back cover on will snap, The electronics then have to be extracted and repaired if possible. If it's viable then the snapped screw studs have to be extracted by either welding on nuts or drilling them out if that fails. The case has to then be shot-blasted and the whole thing reassbled with a new rubber seal etc, all of this takes hours and hours.

Upshot is, if you repair your old radar then you should be able to just clip it back into place and conserve your original calibration. Only downside is you can't guarantee your Radar will be repairable :-/

Wow - there was me thinking there would be some slither of hope I may be able to try something . I’m honestly stuck on what to do. Ive looked on eBay and cannot find the domed shaped radar anywhere. I’m not even that bothered about the radar itself, I just want my stop start to work again. Is there any way I can have a look and see if the radar is functioning or not? The diagnostic code I got from my code reader is “lost communication with front radar sensor” which leads me to believe that the radar sensor is dead…is this right? On a side not my sensor is very wobbly like if if move it with my hand it moves up and down. Is there no way for me to just ignore the sensor and get my stop start to work?
You mentioned that you would consider a postal service for repair - how difficult would me removing the radar be? Like you said there could be no permanent fix for it so I’m just a bit stuck :/

So to conclude: is there no way for me to check if the radar is functioning and it could just be a loose wire or something?
Can I just disable the radar or trick the car into thinking it’s working so my stop start works?
Is it possible for me to unplug and plug the radar back in?
And lastly, how much roughly would you estimate it to be for me to just get a new radar sensor and calibration

thank you so much for shedding some light on all this

 

[davegsm82]

Wow - there was me thinking there would be some slither of hope I may be able to try something . I’m honestly stuck on what to do. Ive looked on eBay and cannot find the domed shaped radar anywhere. I’m not even that bothered about the radar itself, I just want my stop start to work again. Is there any way I can have a look and see if the radar is functioning or not? The diagnostic code I got from my code reader is “lost communication with front radar sensor” which leads me to believe that the radar sensor is dead…is this right? On a side not my sensor is very wobbly like if if move it with my hand it moves up and down. Is there no way for me to just ignore the sensor and get my stop start to work?
You mentioned that you would consider a postal service for repair - how difficult would me removing the radar be? Like you said there could be no permanent fix for it so I’m just a bit stuck :/

So to conclude: is there no way for me to check if the radar is functioning and it could just be a loose wire or something?
Can I just disable the radar or trick the car into thinking it’s working so my stop start works?
Is it possible for me to unplug and plug the radar back in?
And lastly, how much roughly would you estimate it to be for me to just get a new radar sensor and calibration

thank you so much for shedding some light on all this

Yea, unfortunately they are really rare. This type of radar was only fitted between late 2012 and late 2013, after that they moved to a flat-front Radar which you unfortunately can't fit to our cars, there's some sort of software incompatibility in the CAN Gateway that changed between 2013 ->2014.

In answer to your questions;
1) Sounds like when you can't communicate with module 13 (RADAR) in vagcom, then it's either dead, or the fuse is blown for some reason. pull your glovebox down, behind there is your interior fusebox, check Fuse SC32/F32, you should find the diagram online or in your handbook. If you have a multimeter I can guide you through a couple of tests to check that there's power getting to the radar plug.

2) Disabling the radar - as far as I know this isn't possible, people on forums have tried it and said it doesn't work, possibly because of the Component protection expecting to see the radar and not finding it. The Radar does have a lot to do with the Start-stop, and if you remove it, that doesn't work and you can't just convert to 'dumb' cruise control.

3) Postal repair service - obviously nothing would be guaranteed, your radar may be completely and utterly roached internally, or it may be dead-easy to repair, I wouldn't know until I get in there and I'd still have to charge for the time for disassembly/testing etc.

4) Removal of the radar is easy, it's attached by 3x bolts which have little 'pop-out' ball sections at the back. You can literally pull it off, lift from the bottom (sounds like yours may be disconnected already though!) to disconnect the lower one, then wiggle left and right to disconnect the upper 2x. The connector on the bottom you just push the 2x side clips in and pull the connector off.

5) You CAN just unplug and plug the radar back in, just don't remove or adjust the 3x elongated bolts on the back, that essentially sets your calibration. If your mounting plate behind the radar is fine then when you put it back after repair, it should just work again. A lot of folks will tell you that you MUST have it recalibrated, but the truth of the matter is, if you don't adjust the mountings and put it back exactly where it came from then it will be fine, and if it's not then the radar knows that it's misaligned and you won't be able to use ACC.

6) Cost estimate, for a NEW one I'd say it's impossible unless you go to VW themselves, and people's estimates on the forums are about ~£1k, I'd say it will be even more than that as the ADIS calibration itself is going to be £500 plus an hour or two's worth of Labour.

In all honesty, the radar is brilliant, but when they go wrong VW have you right over a barrel.

Dave.

 

[MrBounce]

Yeah I don't see an ACC module there, so looks like it can't be reached on the CANBUS. That suggests you either have a wiring issue, or the radar module is defective.

Thought I'd post my experience of this issue in the hope that it may help anyone experiencing similar issues. My ACC malfunctioned about 6 months ago, I lived without it but a week ago I got the start stop error and lost the parking sensors. I have VCDS and could see the issues with the modules, I did a search but never really found a definitive answer to fix it, so I bit the bullet and took it in to VW for a diagnosis. Have to say they were great, only charged me for 35 minutes, turns out it was just a fuse, Fuse number 32 in the glovebox. Felt a bit daft that thats all it was, and never came across this during my searches, but now everything is working again, so first thing to check is fuse number 32!

 

[IWMTom]

Thought I'd post my experience of this issue in the hope that it may help anyone experiencing similar issues. My ACC malfunctioned about 6 months ago, I lived without it but a week ago I got the start stop error and lost the parking sensors. I have VCDS and could see the issues with the modules, I did a search but never really found a definitive answer to fix it, so I bit the bullet and took it in to VW for a diagnosis. Have to say they were great, only charged me for 35 minutes, turns out it was just a fuse, Fuse number 32 in the glovebox. Felt a bit daft that thats all it was, and never came across this during my searches, but now everything is working again, so first thing to check is fuse number 32!

Begs the question why the fuse blew in the first place!

 

[davegsm82]

Begs the question why the fuse blew in the first place!

From what I understand, the heater that lives in the front of the radar dome can blow, which could potentially take the fuse out with it. The radar will probably still work but there may be a stored error code relating to the heater. AFAIK it can be turned off in VCDS.

 

[isacheema]

Thought I'd post my experience of this issue in the hope that it may help anyone experiencing similar issues. My ACC malfunctioned about 6 months ago, I lived without it but a week ago I got the start stop error and lost the parking sensors. I have VCDS and could see the issues with the modules, I did a search but never really found a definitive answer to fix it, so I bit the bullet and took it in to VW for a diagnosis. Have to say they were great, only charged me for 35 minutes, turns out it was just a fuse, Fuse number 32 in the glovebox. Felt a bit daft that thats all it was, and never came across this during my searches, but now everything is working again, so first thing to check is fuse number 32!

Thanks for the response!
do you think mine would be the same issue? My parking sensors and Auto Park are working fine - is it worth a shot?