Faulty Rear Parking Sensors

[Mccoatup]

Not happy. My 2017 T6 Van came back from the Converters with the rear camera and parking sensors not working. When I engage reverse I just get a 5 second (or so) tone and no parking display or camera image. VCDS pinpointed the nearside rear parking sensor as the problem area so I removed both this one and the 2nd sensor in of the 4 rear sensors and measured them on an ohmmeter. The nearside one showed a short circuit between two of the pins, whereas the second one in did not, so I assumed then this would mean the nearside sensor was faulty. I swapped this with the second sensor in and gave the van to my local VW dealer expecting VCDS to show the fault had now moved to the second sensor but it didn’t. The VW Main Dealer spent 2 hours on this, and concluded the fault is in the wiring between the sensors at the back and control module under the dash. They take they view that this means that the Converters have driven a screw through the wiring somewhere and therefore their time spent is not covered by the warranty. So now I am £200 down and no nearer finding out where the fault lies. Is it possible that 2 sensors can show quite different resistances between their pins yet both be working?

If the fault truly is somewhere in the wiring, can someone point me at the part of the wiring diagram which shows how the individual sensors are wired back to the Control Module. During the Conversion I added a set of spare wires from under the dash to the rear of the van for future use, so if all else fails, I may have to reroute the connections via my own wiring direct to the nearside parking sensor on the rear bumper.

If that is the case then I need to know a) where the control module is under the dash and b) what connections I need to use. I note that the parking sensors have 3 connections. Do all 3 connections go back separately to the Control module or are some of them common to the other sensors?

 

[Pauly]

The control module is directly underneath the steering wheel behind the lower dash panel above the pedals, the module is mounted sideways on the end of the BCM carrier/bracket
Each sensor has three wires, a positive, a negative and a return signal to the PDC control module
The pos and neg connections are common across all four sensors, there are six wires in the loom going to the rear sensors, pos, neg and four return signals

 

[Mccoatup]

Thanks very much Pauly - your prompt response is very much appreciated. That should give me enough now to bypass the problem wiring if I need to, but I will check out what I can of the existing wiring. Part of the problem appears to be that the main wiring channel along the roof is now inaccessible due to the fitting of the Reimo roof, although it's actually less likely that the fault is there if it's a screw that has somehow pierced the wiring loom. Thanks, Bob

 

[Pauly]

No probs let me know if you need any pics or pinouts of the PDC module

 

[Mccoatup]

Hi Pauly. Am getting closer! I am told the return signal not reaching the Parking Control Module from the rear nearside parking sensor is on Pin 5 of the Black Connector on the Control Module. I have also now accessed the relevant connector at the nearside rear of the van, so am in position to do some electrical checks when it's daylight again tomorrow. As it happens one of the spare cables I added to the van while the elevating roof was being fitted goes from right beside the Control Module under the dash to right beside the connector at the rear, so I can easily bypass the offending cable in the van wiring loom even if I can't find the fault in the van wiring loom.

What would be helpful to know is what colour the wire from pin 5 of the Parking Control Module is. This would save me stripping back the covering on the cable loom to find out the colour.
Thanks, Bob

 

[Pauly]

Just sent you a PM with all the connections on it

 

[Davenjo]

Might be a silly question but, if it was working before the conversion and VW believe the fault to have somehow been created by the converters then why aren’t you handing the van back to the converters to fix?

 

[Mccoatup]

No, it's a good question, but the Conversion Company are not electrical specialists, and short of spending a lot of time dismantling some of the conversion, they are not going to be in a position to diagnose and fix the problem. But also, they went above and beyond the call of duty in modifying my van to my demanding specification, and as a result probably made very little profit , so I want to try to do what I can to sort the problem out, particularly as I am a recently retired electronics engineer. Not that I've done much real engineering for a number of years, but the challenge is helping to keep my brain active!

 

[Mccoatup]

Happy now! Connected up a new wire from the Control Module to the Rear Sensor connector. Simply adding it in parallel wasn't enough. I had to disconnect the original wire too -then it burst into life. Can only think a rogue screw from the conversion has shorted the control wire to some other control signal, as it wasn't open or short circuit and had no spurious voltage on it. Will remain a mystery as life's too short. Working now, so I'll leave it at that. Thanks very much Pauly for the wiring diagram - it made all the difference. I owe you one!

 

[Pauly]

No problem, you are a VIP member, your contribution along with everyone else's is what helps us fund this place and be able to provide this kind of info

 

[Andreas Toverud]

Hi guys! Glad it worked out for you. I am facing similar problems. Long beep when putting the car in reverse and blinking light on the parking assist switch. Does anyone have a wiring diagram to help me start out the troubleshooting? Would be greatly appreaciated!

                Address 10: Park/Steer Assist       Labels: 7E0-919-475.clb
Control Module Part Number: 7E0 919 475 E    HW: 7E0 919 475 A
  Component and/or Version: PARKHILFE 8K  H11 0013
           Software Coding: 118104
            Work Shop Code: WSC 02736 790 50316
              ASAM Dataset: EV_VW75XParkAssis8K A01005 (VN75)
                      VCID: 3467FA5B9FCEB4BE40B-8061
3 Faults Found:

1080083 - Rear Parking Aid Sensor(s)
          B107B 13 [009] - Open Circuit
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 104
                    Mileage: 116148 km
                    Date: 2065.14.29
                    Time: 17:12:26

1113107 - Front Parking Aid Sensor(s)
          B10FC 13 [009] - Open Circuit
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 104
                    Mileage: 116148 km
                    Date: 2065.14.29
                    Time: 17:12:26

1079828 - Supply Voltage for Parking Aid Sensor(s)
          B107A 14 [009] - Open or Short to Ground
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 104
                    Mileage: 116148 km
                    Date: 2065.14.29
                    Time: 17:12:01

 

[Ads_Essex]

Mine has just started this today. Haven’t used the van whilst we’ve had snow. The sensors worked fine before, with the pop-top having been fitted in December

 

[Ads_Essex]

Weird - it worked again earlier, and then stopped working again on the same journey.
I wonder if I have water in around the slam-vent things in the rear bumper?
I couldn’t try and listen to the ticking noise of the sensors themselves due to the rain.

 

[Dellmassive]

I had this issue before,

with us it was traced down to "no signal from one of the rear sensors"

checking the wiring diagram we found the loom went from a connector under the passenger seat to the rear of the van, when belling it out we found the signal wire was open circuit for one of the sensors. (intermittently)

on checking the connector at the rear sensor we found that if we connected a temp jumper wire from front junction box to the back sensor at fault it worked ok.

so further investigation showed that a previous rear end "bump" (some t**t drove into us at about 10mph, but no obvious damage), the year before had caused the wire sheath to be damaged and moisture had got into the cable and corroded the copper wire.

we ended up stripping the wire back to clean copper and spliced in a new bit, (on the rear loom to the the rear PDC sensor, about 8 inches)

so far so good a year down the road.

 

[landyman]

Happy now! Connected up a new wire from the Control Module to the Rear Sensor connector. Simply adding it in parallel wasn't enough. I had to disconnect the original wire too -then it burst into life. Can only think a rogue screw from the conversion has shorted the control wire to some other control signal, as it wasn't open or short circuit and had no spurious voltage on it. Will remain a mystery as life's too short. Working now, so I'll leave it at that. Thanks very much Pauly for the wiring diagram - it made all the difference. I owe you one!

hi i got same problem? what colour wire? and under passenger seat?

 

[Mccoatup]

Hi Landyman,
Attached is all the info I accumulated on this topic, including colour coding. Hope that helps!

 

[Dellmassive]

Nice bit of work @Mccoatup

 

[Oggy]

Same issue for me, nice guy that did the conversion but electrics not his strong point.
I get the long beep, when selecting reverse, then nothing. Before I get stuck in or palm it of to a car electrics specialist are there some checks I can do? I have a no knowledge of canbus systems etc but know my way around a multimeter

 

[Ads_Essex]

There is a connector block towards the bottom of your NSR D-pillar - unplug that and blow out any dust. Do the same with each individual sensor. Then try again.

If you have no luck, put the van in reverse without the engine running, mute the PDC on the stereo, and go and listen to each sensor - you should hear it clicking as it sends out a signal. Each sensor should do this. If one doesn’t, that may be your problem: the sensor or the cable feeding it.

Good luck.

 

[Mccoatup]

Apologies for the late reply, Oggy. Maybe it's just my age but I can never hear the parking sensors clicking! But you shouldn't need to know about canbus to diagnose the problem - a multimeter should be fine to check continuity between the Body Control Module below the steering column and the connector in the D Pillar. You can see some pics in the document I attached earlier in this thread. I never did find out what the Converter did to my van as nothing appeared to be shorted or open circuit. I only solved the problem by cutting out and replacing the wire from the BCM to the D pillar connnector for the particular sensor that VCDS said was faulty. I can only think that the control signal wire must have been shorting to another control wire which wouldn't show up as a short or open circuit. The parking sensors themselves can be removed individually so you can check continuity between the sensor connector and the D Pillar connector. It's fiddly, but you don't need to removed any bits of the vehicle to do this. In the unlikely event that a sensor is faulty you can get cheap ones off eBay by reading the part number off the sensor itself once you've taken one out. One thing I was neevr sure about was wehterht eh wiring went via another connector under the passenger seat or not. The seat would have been taken out the Converter , so I did wonder if that was where the damage had been done.
Good luck - And I would be interested to know if you do locate the source of the problem!