PDC Retrofit on Golf MK7 - Front sensors won't work

[Fraysa]

Hey everyone,

I recently completed a retrofit of a PDC PLA 2.0 kit on my 2016 Golf MK7.

The rear is working perfectly, and I took time this weekend to connect the front harness through the firewall. However, when I put in drive, there's an error 'Front parking sensors' on the MFD.

Here's a scan from my control module (will post a full Auto-Scan when I'm near the car):

Sunday,08,November,2020,08:07:37:29935
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 20.4.2.0 (x64)  HEX-V2 CB: 0.4513.4
Data version: 20200730 DS317.0
www.Ross-Tech.com




                Address 10: Park/Steer Assist       Labels: 5Q0-919-298.clb
Control Module Part Number: 5Q0 919 298 K    HW: 5Q0 919 298
  Component and/or Version: PARKHILFE PLA H12 0054
           Software Coding: 0031155051
            Work Shop Code: WSC 12345 123 12345
              ASAM Dataset: EV_EPHVA2CAU3700000 003021 (VW37)
                       ROD: EV_EPHVA2CAU3700000_003.rod
                      VCID: 47CB5F9CAF2ABAC3D39-8012
3 Faults Found:

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: 159
                    Mileage: 43503 km
                    Date: 2020.11.07
                    Time: 21:56:39

13697024 - Control Module
          U110F 00 [009] - I'm sorry Dave; I'm afraid I can't do that!
          [Steuergerät für Bremse - ESP_02.ESP_Status_ESP_PLA - PLA-Codierung in Bremse prüfen]
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 6
                    Fault Frequency: 1
                    Reset counter: 158
                    Mileage: 43503 km
                    Date: 2020.11.07
                    Time: 21:53:26

13639168 - Databus
          U1121 00 [009] - Missing Message
          [Steuergerät für Rear Cross Traffic Alert - RCTA_01 - kein Signal / keine Kommunikation]
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 6
                    Fault Frequency: 2
                    Reset counter: 159
                    Mileage: 43503 km
                    Date: 2020.11.07
                    Time: 21:53:27

I assume the first error is my issue:

1113107 - Front Parking Aid Sensor(s)
B10FC 13 [009] - Open Circuit

However, I made sure that the connection is tight from the control module to the front sensors.

 

[downtime]

So how many parking sensors you have? If 8 you have incorrect module and that’s why you have the errors.

Either change to a correct one (294 instead of 298) or install also the additional 4 side sensors.

 

[Fraysa]

So how many parking sensors you have? If 8 you have incorrect module and that’s why you have the errors.

Either change to a correct one (294 instead of 298) or install also the additional 4 side sensors.

I have 12 sensors (4 center, 2 sides).

I confirmed the continuity of the harness and the relevant pins by using erWIN document and it's all pinned correclty.
Rear is working perfectly, but no voltage going to the front at all.

Could it be a faulty unit?

 

[siLc]

Verify that the front sensors power supply and grounds are good. You can measure them with a multimeter.

Also the coding is a bit off - PLA module is currently expecting to see Side Assist fitted but there is none in reality? A full autoscan will help in this regard...

 

[Fraysa]

Verify that the front sensors power supply and grounds are good. You can measure them with a multimeter.

Also the coding is a bit off - PLA module is currently expecting to see Side Assist fitted but there is none in reality? A full autoscan will help in this regard...

I will post a full auto-scan ASAP when I'm near the car.

As for the power supply and ground - when should I check the voltage? Yesterday I tried to disconnect the female connector of the 8 pin plug on the engine bay side. I had my friend put the car in reverse so it would engage both sensors and then he put a multimeter on pin 8 (12v) and pin 7 (ground) and there was no voltage for both.

We even tried to clear the fault and then try to engage reverse/drive gears but nothing came.

I think it cannot be measured with a multimeter because the system checks for break in wiring by sending a small voltage pulse which cannot be caught by a multimeter.

 

[iichel]

What about a broken sensor?

 

[Fraysa]

What about a broken sensor?

I think a broken sensor would yield a fault code about an individual sensor being faulty, not a circuit error.

 

[iichel]

I agree, you're completely right. But given that you tested all the wiring and that turned out to be OK. Perhaps there is a short-circuit in a sensor?
Other things I can think of is a short to ground in the wiring but that should give another. The open circuit really points towards a broken wire.
Or perhaps a faulty control module?

If I'm not mistaken, all front sensors share a common power supply and GND and have an individual wire going to the PDC sensor for the distance signal.
Perhaps you could disconnect one sensor and verify the voltage and GND on that given connector.

 

[Fraysa]

One thing which I do not understand is this... I took out the front sensor connector on the PLA module and tried to measure the voltage on the pin outs on the module itself. When the car was in reverse/drive none of the pin outs would give any voltage... wouldn't it be the easiest test? Shouldn't the pins give constant 12V while the car is in drive/reverse?

 

[iichel]

I would test this when the car gives out an error. As soon as you put it into drive, I understood, it starts complaining.
So test it then, if possible. I think it's best to measure it with the sensors attached. ]

But, many modules nowadays cut off any power if they detect any errors and... you have an error.
So I'm not sure what to advise. Try it all, if possible.

Did you just measure continuity or load test the wires?
Please do the latter as well to measure any 'asshole' wires with borderline resistance and no load bearing capacity.

 

[Fraysa]

I suspect the module will cut off any power to the front sensors once it detects the issue. However, I'm not sure where the break is so I can't know...

 

[siLc]

You're right, measuring +12v is a bit hard in the current circumstances.

But verifying GND exists at the front bumper connector is easier One lead on the body (or PLA 18pin connector pin 10) and one in the GND pin (body side).

 

[Fraysa]

Throwing an update here that I managed to fix the issue.

I checked continuity from the male connector to the actual sensors and found out that the 12V (red) wire does not pass signal. I looked at the connector, took out the 12V pin (I think it was pin no. 8) and found out the copper wire wasn't correctly attached to the actual pin.

Soldered it again and it worked like magic.

Tip for future: DO NOT buy things from AliExpress!

Thanks a lot everyone =)

 

[iichel]

I have 12 sensors (4 center, 2 sides).

I confirmed the continuity of the harness and the relevant pins by using erWIN document and it's all pinned correclty.
Rear is working perfectly, but no voltage going to the front at all.

Could it be a faulty unit?

No to criticize you in any way whatsoever, in fact I would like to praise you for sharing the solution. Thank you for this.
But I more or less assumed all the wiring was in good shape after the quoted message.

Nonetheless I'm happy you managed to find the problem and share it here. Enjoy your car!