Thursday 26 July 2018

Golf GTI Edition 35 : replacing the interior ultrasonic sensor for alarm


So when I first got the Micro-CAN cable I did a full fault scan. 
http://www.ross-tech.com/vcds/tour/autoscan.php

I expected it to be empty but sadly there was a little surprise...
1 Fault Found:03156 - Sensor for Anti-Theft System (G578)             004 - No Signal/Communication - Intermittent

a quick google search, revealed all might not be well with the alarm system, most likely the ultrasonic sensor.

I also found out that the door LED stays continuously lit for 10-30 seconds to indicate a fault condition. 
You would never notice this unless you stared at it and knew what to look for. I locked the car to prove the LED did so to confirm.
Why not check your car next time you lock it!?


On the assumption the sensor was broken and given that these are well over £100 new , I bought a used item from ebay for £20

VW Golf 6 VI TIGUAN 5N INDOOR SURVEILLANCE ALARM ULTRASONIC SENSOR 1k8951171


then it was time to take the area above my head apart....which was helped by

Removing and installing anti-theft alarm sensor -G578

For me this was


  1. pull down the plastic lip cover that covers the 3 eye like sensors (only 2 are real sensors)
  2. this reveals 2 chrome torx screws that hold the panel up
  3. undo them
  4. pull panel down where sensors are
  5. the panel then drops (being held at the front of the car by some retaining tabs only)
  6. You then have access to all the internals, be careful not to pull on any plugs.
  7. Remove sensor (being careful to only release 3 clips (NOT the smaller edge clips that keep the 2 halfs of the sensor together)
  8. Replace with new (2nd hand) item
  9. Refit

However when I opened the panel up i could see there was no cable actually attached to the ultrasonic unit, that may contribute a little to "No Signal/Communication" !

At this point I was running out of time, it was getting dark and i wasnt entirely sure if for some reason this was a bluetooth or wireless module that didnt need a plug.....so i put it all back together

but i soon realised from this picture on the internet that that wasnt the case...



So the next day I took the panel apart again and started digging around for a cable, luckily I did find it wrapped around a metal body tab.

Re-connected plug

Scanned with VCDS to get 2 fault codes now

1 Fault Found:
03156 - Sensor for Anti-Theft System (G578)
            004 - No Signal/Communication - Intermittent
             Freeze Frame:
                    Fault Status: 00100100
                    Fault Priority: 4
                    Fault Frequency: 1
                    Reset counter: 155
                    Mileage: 34479 km
                    Time Indication: 0
                    Date: 2012.11.17
                    Time: 22:10:30
1 Fault Found:
01044 - Control Module Incorrectly Coded
            000 -  -  - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 35267 km
                    Time Indication: 0
                    Date: 2012.11.26
                    Time: 17:06:39

which I duly cleared, re-scanned to zero faults 

01-Engine -- Status: OK 0000
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
10-Park/Steer Assist -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
2E-Media Player 3 -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
55-Headlight Range -- Status: OK 0000
56-Radio -- Status: OK 0000
62-Door, Rear Left -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
77-Telephone -- Status: OK 0000

locked the car to confirm that now the LED blinks only , with no periods of being lit continuously.

I checked with the previous owner and no knowledge of this.

I can only assume that at some point in the cars early life the sensor was deliberately disconnected to avoid battery drain (or a fault meaning it went off all the time)

Car so far appears to be back to as intended.

Without VCDS I would have been none the wiser..............


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