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Discussion Starter #1
Hi all, VAG fan here. I recently bought my first T5 and wanted to run some diagnostics on it but cant connect to the ECU.
Tests I've already done are:

1. tried with VCDS ( not lite and not genuine, but has worked on all my other VAG cars I've had) - not connected to ECU
2. tried with Bluetooth devices and Torque. Power, but no connection.
3. tested pin 16 and 4 - 12v .
4. tested K line pin - 12v
5. checked ECU for any obvious signs of problems externally.
6. disconnected battery for an hour

Other thing to note is I only have 1 key and the remote fob doesn't work, not sure if it's related though but worth mentioning.

Van runs ok, but does have a slight oil leak around the tandem pump which I aim to replace as iM sure it's faulty given the engine starts badly cold or hot so assuming there's a drop in fuel pressure somewhere.

My thinking is either one of the following in no particular order:

1. wire broken / shorted somewhere
2. clocks malfunction
3. other control module issue
4. ECU problem

Also worth mentioning that there's still the original stereo in the van (the tape player one! Who had tapes in 2005!?)

What with the virus causing lock-down I cant get much help away from home, so was wandering what to try next as Im self employed and basically not working at the moment sadly.

Any help or advice appreciated. I'm based on Cornwall / Devon border if that makes any difference.

177662
 

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Hi all, VAG fan here. I recently bought my first T5 and wanted to run some diagnostics on it but cant connect to the ECU.
Tests I've already done are:

1. tried with VCDS ( not lite and not genuine, but has worked on all my other VAG cars I've had) - not connected to ECU
2. tried with Bluetooth devices and Torque. Power, but no connection.
3. tested pin 16 and 4 - 12v .
4. tested K line pin - 12v
5. checked ECU for any obvious signs of problems externally.
6. disconnected battery for an hour

Other thing to note is I only have 1 key and the remote fob doesn't work, not sure if it's related though but worth mentioning.

Van runs ok, but does have a slight oil leak around the tandem pump which I aim to replace as iM sure it's faulty given the engine starts badly cold or hot so assuming there's a drop in fuel pressure somewhere.

My thinking is either one of the following in no particular order:

1. wire broken / shorted somewhere
2. clocks malfunction
3. other control module issue
4. ECU problem

Also worth mentioning that there's still the original stereo in the van (the tape player one! Who had tapes in 2005!?)

What with the virus causing lock-down I cant get much help away from home, so was wandering what to try next as Im self employed and basically not working at the moment sadly.

Any help or advice appreciated. I'm based on Cornwall / Devon border if that makes any difference.

View attachment 177662
Check Kline for continuity to ECU
 

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Discussion Starter #6
Actually which Pin do i test on the ECU or is there a link to a schematic i can find?
 

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Discussion Starter #7
OK done a test now according to this vid:
Worrying readings is this i presume:

Pin 7 - k-line - 11.5v

I think it should be 3.5-4v? There is no after market stereo - although im not sure but it's an old VW blaupunkt - disconnected now anyway.

After disconnecting the batery i tested pins with the following results:

Pin 4 - GND - 300 mOhm
Pin5 - GND - 300 mOhm
Pin7 - K-Line - 45kOhm!!

I'm not sure i trust those readings 100% as it's a cheap multimeter, but does highlight an issue with Pin7

Checking pin 43 on the ECU next will post up what that reads.

I'm assuming there's problem with a control module ( BCM or cluster im guessing based on common issues) or ECU.
 

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Discussion Starter #8
Oh dear I've now got bigger problems..

Ive managed to turn the van into a brick! After trawling the net and forums/ videos etc for common faults I did the following:
  1. First i disconnected the ABS plug as there was some water on the top - thought it may have caused an issue. Again tested OBD2 with key in and turned to first click - no changes.
  2. Put the plug back in after drying out and inspecting the terminals.
  3. I took the cluster out to see if that was causing the issue, whilst doing so I put the key in to test to see if the OBD2 worked which i think has caused the problem.
  4. No change in OBD2 connection so put it back in.
  5. Now i get the key light flash and ABS lights Traction control and the red ! all going off. Start the car and it turns over then stops. So I've deprogrammed the key somehow.
Bad timing as the van is blocking the driveway so Cant get it moved, don't think I can get a technician out to take a look either. I'm a bit lost at what to do next.

New cluster? New ECU? second hand set of clock / ecu and keys? Funds are short as im self employed at the moment and have little to no work on.

:poop:
 

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Before you do anything more drastic, disconnect the engine battery, leave it for 10 minutes, reconnect and test it all again.
 

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Discussion Starter #10
Thanks for replying, yeah i did try that.

I guess it would be ok if I could get the obd2 working as i can use vag tacho and vcds. But without that access im buggered.
 

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Discussion Starter #11
OK panic over, van is running again. Managed to find that the cluster has a l,oose connection at the back, i must have broken part of the clip when i took it off without realising. Fits back in ok.

Now pbak to the original problem with Obd2 with no signal. Guess i'll have to check and trace the wiring loom? Not looking forward to that tbh

Noticed a couple of other things that don't work
  1. central locking doesn't lock passenger door but does for the sliding door.
  2. head light beam height adjustment does nothing
  3. airbag light is now on
 

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Discussion Starter #13
Central locking faults can be corroded wiring under drivers seat where wiring runs under rubber flooring
Yeah i've seen videos on that - where they've added the water pump for the sink it's come from under the driver seat so maybe an issue there somewhere. I'll take both seats out and check under the matting hopefully will see something obvious.

Air bag light will need to be done on diagnostic
Thought as much (y)

Headlight could be switch, headlight motor, wiring
Probably wiring again as neither side is working? Unless both motors have packed up.

Are there any good schematics online anywhere?
 
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