# Electronic Boot Release Not Working



## Nipun (Dec 7, 2020)

Hi guys, as above my boot release has randomly stopped working (I can still get in using the emergency release cable inside).

Neither the switch in the door or the fob opens the boot, however the indicators do flash when I press and hold the fob button to try an open it. Central locking is still working fine. Fuel flap is working normally.

I have removed the trim to access the boot release mechanism. I removed the 3 pin plug and connected my multi-meter to both live wires on the plug to check for voltage. One wire is giving a constant 11ish volts and the other is giving around 11 volts too only when I press the fob button. Surely this must mean my wiring is okay and it is the release mechanism which is faulty?

VCDS is throwing the below code:



> 1 Fault Found:
> 00950 - Central Locking Motor - tailgate (V53); UNLOCK
> *007 - Short to Ground*
> 
> ...


I used the live data function on VCDS to test the door switch, and it says "unlock" each time I press it so I assume this is not at fault. Also checked all fuses in the dashboard fusebox which are all okay.

I'm not to sure what VCDS means by "short to ground"? Would this indicate that boot release is faulty or a wiring issue? What does it mean by Terminal 15/50 OFF?


----------



## MT-V6 (Jan 11, 2015)

Do you hear any noise from it unlocking or trying to unlock? It could either be the lock mechanism or alternatively a break in the wires in the hinge grommet, which could be causing the short


----------



## SwissJetPilot (Apr 27, 2014)

+1* MT-V6* - I found this picture on another Forum where the wires in the hatch grommet have broken. This is not too uncommon in the drivers and/or passenger doors too when door locks, windows or any of the switches in the doors fail to work.









The expression "short to ground" is also known as a "short circuit". This means to have a direct connection to ground (earth); in this case either a broken wire as shown inside the grommet or possibly a broken winding wire inside the motor. If you replace a blown fuse and it blows again as soon as power is applied, a broken wire somewhere in the circuit may be the cause. A bit of testing with a multi meter should be able to track down where the failure is located. This Youtube will explain how to find a short circuit in more detail -

*How to Diagnose and Find a Short Circuit or Wire in Your Car*
https://www.youtube.com/watch?v=M4LGykZ ... ndWrenches

"Term 15 Off" means: With terminal 15 switched off. I believe (and stand to be corrected) that Terminal 15 refers to battery power with ignition switch on or off. It can also register DTC 0_0576 - Terminal 15: Electrical Fault in Circuit_.
http://wiki.ross-tech.com/wiki/index.php/00576

As shown below, this is a typical 12-VDC motor one finds scattered around a vehicle; (e.g. door locks, gas cap relay, HVAC vent servos, etc.). The winding (wire that makes the motor) is covered in insulation, in this case you can see it as a blue color. If this insulation fails, or if the wire breaks and touches the case, then it can cause a "short to ground" fault.









If you need a reference to the wiring diagram shown below, you'll find it here - 
*FAQ - Audi TT (8J) Workshop Manuals & Self Study Programs*
https://www.ttforum.co.uk/forum/viewtop ... &t=1833829


----------



## Nipun (Dec 7, 2020)

MT-V6 no noise unfortunately which makes me believe the motor has packed in?

SJP - Thanks very much for your in-depth answer. I have visually checked the wiring (where possible) for breaks but it all seems good. I pulled back the grommet housing as much as possible and there seems to be no break there.

Checking for continuity has me a little confused to be honest. I am getting resistance between ground from the plug to the ground point in the rear lid.

When I use the "Advanced Measuring" on VCDS to check the switch in the door, the range is "UNLOCK, Not Operative and No Communication". When I pull the switch it says "UNLOCK" and when I let go it goes back to "Not Operative", which is the same as the fuel flap which is working. Now does this just check the switch or does it check the switch and wiring up to the plug?

As the car is under warranty I think I may just book the car in with Audi, I'd be surprised if it isn't covered.


----------



## Knight-tts (Jan 29, 2019)

I had similar problem mine failed and would not close when using the switch the tailgate lock was not make no audio clicking , I just replaced the locking mechanism on tailgate and all good, think the part cost £60 new (8P4827505C) and 30 mins to fit myself


----------



## SwissJetPilot (Apr 27, 2014)

Yep, go with the Warranty!  And if you enjoy a little forensics, ask for the parts back and you can open it up and see what's inside and maybe determine how and why it failed. Would be a nice share for the Forum. ;-)


----------



## Nipun (Dec 7, 2020)

So I had a real run around with this one!

Booked the car in with Audi. Despite the warranty, I had to sign a waver stating the cost for diagnostic labour would be £120 for the first hour if they could not find any faults with the boot lock. Pretty standard, as I've had to do this many times with warranties and it is not payable if a fault is found.

They kept the car for the whole day and totted up a £400+ bill (just for diagnostics!). They said most likely the module has failed as suggested by Knight-tts but they have to check the wiring in order to ensure the job is completed properly. And this would incur even more labour costs. Obviously this all would be covered under warranty if the module is at fault, but if it was the wiring then they said I would have to pay for the diagnostics which were approaching £600.

Naturally I was getting a little uneasy at the potential costs in-case it was the wiring, so I got them to release the car for free under good-will and said I'd sort it out myself. The module is only £51 from Audi.

Got home, tried opening the boot and both the door and fob are now working! I connected up VCDS and the below fault codes were thrown when the technician was diagnosing the car. Cleared them, and they haven't returned and the lock is working exactly as it should. Very confused! Not sure what they have done (if anything) but "Central Locking Thermal Protection" is a code I haven't seen before...


```
Address 09: Cent. Elect.       Labels: 8P0-907-063.clb
Control Module Part Number: 8P0 907 063 H    HW: 8P0 907 063 H
  Component and/or Version: BCM PQ35  H   108 0615
           Software Coding: 46000B2FA005F1202070C9E00000094C521E58AA3000D928DC000E440045
            Work Shop Code: WSC 01236 758 00200
                      VCID: 392F266CB957691388D-806C
3 Faults Found:

00950 - Central Locking Motor - tailgate (V53); UNLOCK 
            007 - Short to Ground - Intermittent
             Freeze Frame:
                    Fault Status: 00100111
                    Fault Priority: 4
                    Fault Frequency: 1
                    Reset counter: 178
                    Mileage: 98284 km
                    Time Indication: 0
                    Date: 2021.04.24
                    Time: 12:40:16

             Freeze Frame:
                        Term 15 On
                    Voltage: 11.95 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        OFF

01565 - Luggage Compartment Light (W3) 
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 4
                    Fault Frequency: 4
                    Reset counter: 178
                    Mileage: 98333 km
                    Time Indication: 0
                    Date: 2021.04.28
                    Time: 13:58:39

             Freeze Frame:
                        Term 15 Off
                    Voltage: 13.50 V
                        OFF
                        ON
                        Term 50 Off
                        OFF
                        OFF

01038 - Central Locking Thermal Protection 
            000 - - - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 6
                    Fault Frequency: 1
                    Reset counter: 178
                    Mileage: 98333 km
                    Time Indication: 0
                    Date: 2021.04.28
                    Time: 14:02:18

             Freeze Frame:
                        Term 15 On
                    Voltage: 13.50 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        OFF
```


----------



## SwissJetPilot (Apr 27, 2014)

@ *Nipum* - Would you be so kind and put in front of your diagnostic text and at the end (Use brackets [ ] not < >) and it will make the text look like this window with a slider. It just saves space when you want to post your Auto Scan text files -


```
Address 09: Cent. Elect. Labels: 8P0-907-063.clb
Control Module Part Number: 8P0 907 063 H HW: 8P0 907 063 H
Component and/or Version: BCM PQ35 H 108 0615
Software Coding: 46000B2FA005F1202070C9E00000094C521E58AA3000D928DC000E440045
Work Shop Code: WSC 01236 758 00200
VCID: 392F266CB957691388D-806C
3 Faults Found:

00950 - Central Locking Motor - tailgate (V53); UNLOCK
007 - Short to Ground - Intermittent
Freeze Frame:
Fault Status: 00100111
Fault Priority: 4
Fault Frequency: 1
Reset counter: 178
Mileage: 98284 km
Time Indication: 0
Date: 2021.04.24
Time: 12:40:16
```
Here's the Ross Tech wiki. Just Google "Ross Tech xxxxx" where xxxxx is the fault code. As noted, it could be the lock is sticking, which could cause the motor to "warm" up a bit since there's more electrical resistance as the motor tries to turn resulting in a thermal fault. You may want to use some electrical contact cleaner (it doesn't leave any residue like WD-40) and give it a good clean.

Most modern automotive motors have a thermister or other similar circuit protection devices built into them. Basically it's an over current protection device, think of it like a self-setting fuse. If you apply power to an electric motor and it can't turn, the windings turn into a heater and would burn out the motor. If you ever played with electric trains as a kid, when the locomotive electrical motor got jammed from carpet fuzz, it would overheat and give off a burned smell. However wIth a circuit protection device in the circuitry, it warms up to a pre-set condition, and then "trips" to protect the motor. When the fault goes away (you stop applying power) it cools and resets. This may explain the intermittent issue.









Here's a good article on automotive circuit protection if you're interested -

*Circuit Protection Automotive Devices*
https://www.eeweb.com/circuit-protectio ... e-devices/


----------



## MT-V6 (Jan 11, 2015)

Just out of interest, what module did you buy for £51? This sounds extremely cheap as most are in the hundreds


----------



## Nipun (Dec 7, 2020)

SJP - Thank you, I was attempting to display the scan like that but wasn't entirely sure how. Good to know for future posts too 

With regards to the motor sticking and overheating, maybe your onto something, a few weeks ago I plastered it with white lithium grease :lol: . Maybe on the inside it has gone all chalky and gummed up? I will give it a good blast with some contact cleaner however it has been working okay since my visit to the dealer.

MT - The part I was referring too was the lock assembly 8P4827505D. I didn't buy it in the end as mine is working now but that's the price at Audi Leicester. Cheapest I could find to be honest.

Since owning this car I probably have gotten 90% of my parts new from the dealer and they're usually the cheapest. For example, the wing mirror bracket (8J2857539) which the soft screw gets seized into, I messed the threads up drilling mine out, new from Audi they are only £19.50 each. Not bad in my opinion. And the screw replacement repair kit was only like £2 from them.


----------

