[Pickledog]

Anyone?

 

[Or_GazM]

Cheap and easy thing to try...
Just don't buy a cheap Chinese switch....
The VW one is common with many VAG vehicles.

 

[Pickledog]

I'll let you know...?

 

[Pickledog]

Ignition switch replaced
Retaining screw lug broke as I was fitting it
Engine seems to be responding better
Still won't run without the live from the battery to the solenoid
Counting to ten........................................................................

 

[tomo]

Thanks cyclist rob for the info! Turned out to be a broken wire in the engine bay.

 

[jirip]

REF A, continuity test, relay hole #8 (relay pin87) to pin 10 in terminal G7, to check fuse box. If ok check wire from plug G1 pin 10 to ECU T121 pin 1 and 2 (via ECU fuse) Black and Yellow.

Can someone please give me closer guidance for this?

• Relay hole #8 - what hole exactly? For the 109 relay which goes into position #3, there are only 7 holes for pins. And the relay's pin 87 goes into hole #1?
• Where are the G terminals, ECU T212 pins and ECU fuse?

Thank you!

 

[madoc]

Ths thread (and others) helped me solve my relay 109 issue
I had an intermittant issue and put in a switch to the shut off valve, in the end. Finally the relay would not do the job at all and I'd lost negative, from the ECU, as explained on this thread

By following the instructions, I narrowed it to the fuse board, and eventually jumpered around it. Yes it's a bodge but it works correctly and secure.

I would add the following:

1. The fuse board on a 2.5tdi is a mare to lower enough to get at the connectors on the back. As noted, in this thread, the black and white wire goes to a white connector in the middle of the fuseboard - THIS CONNECTOR IS NOT DIRECTLY BEHIND THE RELAY; IT IS LOWER DOWN. It is very difficult to get at it with normal human hands and arms - I actually spliced by jumper wire into the engine bay and then into the loom, rather than attempt to get it out BUT I already knew the issue was fuseboard.
   There is a little L shaped "bar on the right of the fuseboard that comes out about 1/4" or so to release connectors - it's not obvious as it's flush with the fuseboard when "in".
2. Pop the cover off the top ECU wires to find the right pin on the top - the numbers are tiny but there is only one black/white wire in the right area.

this diagram was really helpful:

 

[flipmedia]

Is this a valid test for checking continuity of run from 85 to ECU - black & white wire... As follows:-

With 109 Relay removed. Set the multimeter to continuity, put one probe in 85 pin slot (I used folded paper clip) and the other probe to chassis ground, turn on the ignition. If you get continuity between 85 pin slot and ground then black & white wire run is good... otherwise, no continuity black & white wire be broken. Am I missing something this seems to be a way to test this run without messing with conduit or fuse panel - aside from removing 109 relay?

I still need to actually inspect the black and white wire as the continuity test is failing using the above method and will repeat continuity between ECU and 85 pin... before giving the black & white wire a good tug - credit to @upspex love that advice.

Other details for the record...

I have 12v on pin 30 fulltime. 30 to 87 wire loop, glow plug light and engine starts. Ground pin 85 glow plug light and engine starts.

I am following this thread after my alternator failed and soon after when I went to start the van to deliver to the garage I found the "no glow light" fault and would not start...

I wonder why this wire failed (if it is this wire) when it did? Is it possible that the van running without an alternator so at 11.8v resulted in failure in some way?

Here's hoping I find the black & white wire fault.

 

[B@man]

Maybe the loom was disturbed when the alternator was replaced causing the wire to finally break ?

 

[Philip C]

Hello All,
Seeing myself and a few others have been having trouble with the van not starting but having no GLOW plug light when turning the ignition on, but engine is turning but not starting.
I had a lot of help from other forum members A: so I thought I put something back.

I AM NOT A VAN MECHANIC. I am going to be quoting plug/pin/wire numbers/colours BUT THEY MIGHT NOT BE THE CORRECT ONES IN YOUR VAN. So I may NOT be correct in some of the things written below. Hopefully thou this will give you a idea/pointers/starting point.
But before I start here are a basic observation;
Part of the key ignition switch goes to relay 109 “engine control module power supply relay”, 109 “coil” side goes to ground Via the ECU. 109 “switch” side goes ECU fuse and then into the ECU. SO if 109 has no earth it can’t “switch on” power to the ECU so it’s not doing it’s “thing” when engine is cranked over = no start.

A multi meter and spare wire/cable will be very handy!

This is what I did ON A T4 65KW 2.4 TDI AJT engine.
Check fuse’s inside the van, below right of the steering wheel and fuses inside the engine bay normally in front of battery. (In a black cover/box) if they all ok.
Find relay 109 (2nd row up 3rd one in from left) remove it and test Voltage at slot 4, slots should be numbered. (Terminal 30 slots into 4) page 80/3 VW Books It should read 12V. If not it’s power supply to the relay. (can’t help you on this one!)

If 12V there, take the removed relay 109, there should be a little circuit diagram on the side, get a small length of wire and join it to terminal 30 then terminal 87, so you got a small loop, basically you bypass the switch in the relay. Put the relay back in the fuse block/box.
Put in key and see if the glow plug light comes on and try starting.
IF it works it be relay 109 OR relay (fuse) box OR wiring.
If not it’s fuse box/ wiring to the ECU fuse. (Goto REF A for further T/S)

Simple test remove wire loop from relay, connect one end of wire to terminal 85 of 109 relay. the other end of wire put to ground (so long bit of wire be good) you should hear a click, turn key and see if glow plug light is on and start van. It still no go, looks like the relay is U/S (you could take cover off relay and hook it up to 12V to double check).

If the van started, it’s the earth side of the relay = fuse box/wires

Quick check the wires/plug on the back of the fuse box. You looking for plug G1 it's white (middle one of 3 white plugs, bottom row) Central Electric 2 THIS MIGHT NOT BE YOUR YEAR/MODEL but give you a idea. It could be a loose wire, look for a black and white wire.
If looks all ok, remove the white plug, best to un hook the side clips on the fuse box and let it hang, there is a little lever on the right side in-between the two row of plugs slide/pull it to the side. (Release’s the lock on the plugs)

Now we check the continuity of the circuit inside the fuse box. Remove relay 109, put one wire of the multi-meter in relay hole #5 (relay pin85) to pin 7 in terminal G7. (Make sure you on right pin)
If all ok it’s not fuse box.
Next step is to check the continuity of the wire (black & white) going from Plug G1, pin 7 to pin18 T121 which is the ECU. Bigger of the two connectors into the ECU (in front of Battery, low down)
I got access to back of the plug to see the wires and found which pin the black and white wire goes into. So if there is continuity looking like you ECU and you need to get a 2nd opinion!

REF A, continuity test, relay hole #8 (relay pin87) to pin 10 in terminal G7, to check fuse box. If ok check wire from plug G1 pin 10 to ECU T121 pin 1 and 2 (via ECU fuse) Black and Yellow.

If the Black and White wire failed the test, it is the wire, it is a long wire loam that comes in the engine bay drivers side then over the front/top of engine etc to the ECU. Just below the brake master cylinder is a common place for a break. Remove wires from the cable wrap/protector and fine the black and white wire and trace/insp it.

If you can’t see anything on the top, easy access to the wire, you can break down the continuity test by removing a LITTLE insulation of the black and white cable and then test plug G1 pin 7 to you new test point. Best also test from new test point to pin 18 in the ECU plug. Hopefully you now know which half/section of wire it is. (Don’t for get to re-protect the wire with tape after. I

Hope this helped. Below are some links that I found help full. (Most found in T4fourm)
And a big THANKS to Stero Steve, kfphil, nogdo, Tim at Phirm and my mate Chris M for helping me.A:


VW Books
Central Electric 2
VW Books
VW Books
http://www.vagcat.com/epc/cat/vw/TR/

Hi Cyclist Rob
First of all many thanks for compiling this very helpful post - it is very helpful.
My father-in-law & I (complete amateurs) were restoring a 1999 T4 Caravelle TDI 2461cc SWB during lockdown and after passing the MOT all was going perfect aside from a brake command unit problem & a failed gear linkage which were sorted fairly quickly.
Then an intermittent electrical problem started with finished with the problem described in your post above.
I’ve just tried the wire loop between 87 & 30 test and the T4 started perfectly and ran perfectly.
Could I just ask, is it ok to just leave the wire loop in place or will that lead to other problems?
If not I’ll start working thru the various elimination stages you describe.

 

[Philip C]

[/QUOTE]
Hi Cyclist Rob
First of all many thanks for compiling this very helpful post - it is very helpful.
My father-in-law & I (complete amateurs) were restoring a 1999 T4 Caravelle TDI 2461cc SWB during lockdown and after passing the MOT all was going perfect aside from a brake command unit problem & a failed gear linkage which were sorted fairly quickly.
Then an intermittent electrical problem started with finished with the problem described in your post above.
I’ve just tried the wire loop between 87 & 30 test and the T4 started perfectly and ran perfectly.
Could I just ask, is it ok to just leave the wire loop in place or will that lead to other problems?
If not I’ll start working thru the various elimination stages you describe.

 

[Jj1991]

Gotta love these forums vans sat for a month or so new battery and a can of easy start later with no joy a quick google search I stumbled across this. She’s now up and running 🙌🏻🙌🏻🙌🏻🙌🏻

 

[Euro_look_manc]

Hello All,
Seeing myself and a few others have been having trouble with the van not starting but having no GLOW plug light when turning the ignition on, but engine is turning but not starting.
I had a lot of help from other forum members A: so I thought I put something back.

I AM NOT A VAN MECHANIC. I am going to be quoting plug/pin/wire numbers/colours BUT THEY MIGHT NOT BE THE CORRECT ONES IN YOUR VAN. So I may NOT be correct in some of the things written below. Hopefully thou this will give you a idea/pointers/starting point.

But before I start here are a basic observation:

1) Part of the key ignition switch goes to relay 109 “engine control module power supply relay”, 109 “coil” side goes to ground Via the ECU. 109 “switch” side goes ECU fuse and then into the ECU. SO if 109 has no earth it can’t “switch on” power to the ECU so it’s not doing it’s “thing” when engine is cranked over = no start.

2) A multi meter and spare wire/cable will be very handy!

This is what I did ON A T4 65KW 2.4 TDI AJT engine. Check fuse’s inside the van, below right of the steering wheel and fuses inside the engine bay normally in front of battery. (In a black cover/box) if they all ok.

Find relay 109 (2nd row up 3rd one in from left) remove it and test Voltage at slot 4, slots should be numbered. (Terminal 30 slots into 4) page 80/3 http://www.vwbooks.co.uk/vw_info/T4_pdfs/vw_T4_engine_wiring_2002.pdf It should read 12V. If not it’s power supply to the relay. (can’t help you on this one!)

If 12V there, take the removed relay 109, there should be a little circuit diagram on the side, get a small length of wire and join it to terminal 30 then terminal 87, so you got a small loop, basically you bypass the switch in the relay. Put the relay back in the fuse block/box. Put in key and see if the glow plug light comes on and try starting.

IF it works it be relay 109 OR relay (fuse) box OR wiring. If not it’s fuse box/ wiring to the ECU fuse. (Goto REF A for further T/S)

Simple test remove wire loop from relay, connect one end of wire to terminal 85 of 109 relay. the other end of wire put to ground (so long bit of wire be good) you should hear a click, turn key and see if glow plug light is on and start van. It still no go, looks like the relay is U/S (you could take cover off relay and hook it up to 12V to double check).

If the van started, it’s the earth side of the relay = fuse box/wires

Quick check the wires/plug on the back of the fuse box. You looking for plug G1 it's white (middle one of 3 white plugs, bottom row) http://www.a2resource.com/electrical/CE2.html THIS MIGHT NOT BE YOUR YEAR/MODEL but give you a idea. It could be a loose wire, look for a black and white wire.

If looks all ok, remove the white plug, best to un hook the side clips on the fuse box and let it hang, there is a little lever on the right side in-between the two row of plugs slide/pull it to the side. (Release’s the lock on the plugs)

Now we check the continuity of the circuit inside the fuse box. Remove relay 109, put one wire of the multi-meter in relay hole #5 (relay pin85) to pin 7 in terminal G7. (Make sure you're on right pin). If all ok it’s not fuse box.

Next step is to check the continuity of the wire (black & white) going from Plug G1, pin 7 to pin18 T121 which is the ECU. Bigger of the two connectors into the ECU (in front of Battery, low down).

I got access to back of the plug to see the wires and found which pin the black and white wire goes into. So if there is continuity looking like you ECU and you need to get a 2nd opinion!

REF A, continuity test, relay hole #8 (relay pin87) to pin 10 in terminal G7, to check fuse box. If ok check wire from plug G1 pin 10 to ECU T121 pin 1 and 2 (via ECU fuse) Black and Yellow.

If the Black and White wire failed the test, it is the wire, it is a long wire loam that comes in the engine bay drivers side then over the front/top of engine etc. to the ECU. Just below the brake master cylinder is a common place for a break. Remove wires from the cable wrap/protector and fine the black and white wire and trace/insp it.

If you can’t see anything on the top, easy access to the wire, you can break down the continuity test by removing a LITTLE insulation of the black and white cable and then test plug G1 pin 7 to you new test point. Best also test from new test point to pin 18 in the ECU plug. Hopefully you now know which half/section of wire it is. (Don’t for get to re-protect the wire with tape after. I

Hope this helped. Below are some links that I found help full. (Most found in T4fourm)
And a big THANKS to Stero Steve, kfphil, nogdo, Tim at Phirm and my mate Chris M for helping me.A:

http://www.vwbooks.co.uk/t4.htm
Central Electric 2
VW Books
VW Books
http://www.vagcat.com/epc/cat/vw/TR/

I just want to add to this even though the thread is old.
I tried everything and go nowhere. After 2 day i managed to get the light on by leaving the ignition on for 20 minutes.
I was shocked plus happy. So started the van then it cut out. I messed with the wires across the engine and found After hours a black wire . Just black and tiny looking bad . I bent it and looked. It was held by 1 strand . So long story short. Look at the black wire too. I made the 109 relay click and yes my coil light came on.

 

[Helidave1]

Hi All,
I have a 2003 888 special which just hit 200,000 miles and has been, without doubt, the most reliable vehicle I have ever owned. However, it recently started to have an issue with the tacho and oil alarm ( I gather these are linked together - no rpm = an assumed no oil pressure = alarm) It started as an intermittent fault but is now more or less permanently present. I noticed recently that the glow plug lamp was also no longer coming on when the key is first turned on but after a few seconds the other lamps go off and the van starts as normal.
I ran a VCDS scan and get 18058 Power Train Data Bus error P1650 under 01 Engine and a similar message in 17 Instruments section 9Missing message from instrument cluster - intermittent fault. I have inspected the wiring as best I can and found no broken wires, loose connections, etc as far as I could see.
Whilst rechecking the wiring today I found that if I remove relay 109, try to start the van (which of course will not start) replace relay 109 and hey presto, the tacho works perfectly, no oil alarm also. The coil lamp still does not illuminate however. If I try the same technique by simply removing relay 109, re-inserting it, and then starting the van the tacho fault is still present, it only clears when I remove the relay, attempt to start the van, and then re-insert the relay.
Has anybody had a similar problem?
Cheers

David

 

[Euro_look_manc]

Hi All,
I have a 2003 888 special which just hit 200,000 miles and has been, without doubt, the most reliable vehicle I have ever owned. However, it recently started to have an issue with the tacho and oil alarm ( I gather these are linked together - no rpm = an assumed no oil pressure = alarm) It started as an intermittent fault but is now more or less permanently present. I noticed recently that the glow plug lamp was also no longer coming on when the key is first turned on but after a few seconds the other lamps go off and the van starts as normal.
I ran a VCDS scan and get 18058 Power Train Data Bus error P1650 under 01 Engine and a similar message in 17 Instruments section 9Missing message from instrument cluster - intermittent fault. I have inspected the wiring as best I can and found no broken wires, loose connections, etc as far as I could see.
Whilst rechecking the wiring today I found that if I remove relay 109, try to start the van (which of course will not start) replace relay 109 and hey presto, the tacho works perfectly, no oil alarm also. The coil lamp still does not illuminate however. If I try the same technique by simply removing relay 109, re-inserting it, and then starting the van the tacho fault is still present, it only clears when I remove the relay, attempt to start the van, and then re-insert the relay.
Has anybody had a similar problem?
Cheers

David

Ive not had that problem mate but definitely check the wires across the engine. There was a few on mine looking like they would fail anytime soon. Good place to start

 

[Helidave1]

Ive not had that problem mate but definitely check the wires across the engine. There was a few on mine looking like they would fail anytime soon. Good place to start

Cheers,
I started looking at the wires but once I realised that taking out the relay, trying to start the van, replacing the relay cured the problem I sort of went off on a tangent. It seems almost like a capacitance issue and attempting to start the van without the ECU power somehow grounds the line and clears the issue. I have to go over to Ireland for a few days and don't get back until Friday so looks like I will have a busy weekend chasing cables!

 

[Helidave1]

For anybody else that has the same problem (tacho erratic, oil alarm but car starts and runs fine) the problem is the wiring loom across the engine block. Over the 20 year life of my vehicle, the wiring loom has chaffed against the corrugate cable protector to the extent that several wires actually looked like they had had mouse damage! I replaced/repaired where required, wrapped the whole section in loom tape and then put it back in the plastic enclosure - van is now back to its normal self and checked with VCDS and all errors cleared.

 

[Tomorrow Bacon]

Hello all, longtime reader, first time poster

A little history of the electrics of the 2003 t4 2.5tdi 75kw lwb i purchased in 2016.

Within the first few months a smell of burning and little wisp of smoke came up from the steering column on a couple of separate occasions whilst driving but nothing noticeable stopped working at that exact time.

The central locking stopped working before or after that within the first year of ownership (wasn’t taking too much notice as i was just happily travelling around europe without much care)

2022 after 4 years of living with an increasingly erratic power on/warning beep from an inherited nokia/vodafone mobile phone setup (including wired microphone placed above, phone charger cradle mounted to the central air vents, mini remote control mounted on drivers side air vent, wired plastic disc on the dash (possibly an aerial?) and powerpack and possibly modem hidden behind the lower central panel (behind the gearstick), unprovoked wiper swishes and a radio cd player that randomly turned itself off and spat cds out I decided to clear the clutter out.

Few months later I had to replace the battery.

Now after one year of fairly good going i suddenly lose all power and cut out. No response on trying to start again, no dash lights, nothing. The breakdown service can’t start it. The garage hold it for 6 weeks trying different things and i end up with a new alternator belt, distributor and repaired injection pump. Works perfectly for 5 days, day 6 drive 5 minutes and motor cuts out with warning beep and oil and battery light up on dash. Sit for 10 minutes trying the key over and over until glow plug light appears and it starts and i drive back home. Next day Look on this forum and come across this thread. Next day try again and get 6 minutes down the road and cuts out again, same warnings on dash. Sit for 15 minutes trying the key, wiggling the relays gently, unplugging, replugging until the glow plug light appears and it starts. Yesterday check all fuses, connections, relays and fusebox for discrepancies/damage, nothing visible, then onto the top engine bay loom (as i have no multimeter at the moment) and i find a black and white wire u-turning within some tape and going back towards the fusebox, not following on with the rest of the wires towards the ecu?

Is this strange?

I have been reading as much of this thread as possible but it is quite an epic to get through and i apologise if this has been dealt with before and i’ve somehow missed it. In the meantime I’m off to check the steering column wires. Back soon.

Yours sincerely
Tom

 

[Gazza-SW]

I would just like to add a big thank you to the OP Cyclist Rob, for his fabulous trouble shooting routine (1st post in this thread) it really helped me (and my 2.5 tdi AJT) and yes I had a break in the black & white wire, all fixed and I am back on the road. Thank You Rob

 

[yellowgit]

Nice thread. Thanks as just managed to fix my non-starter (2001 ex-aa 2.5tdi). It was, luckily, just a 109 relay (1J0906381A) problem which a replacement fixed.
I'd replaced it 9 years ago for the same problem - so just proof that they don't live for ever.
I opened up the old one but it looks as good as new inside. Ah well.
Anyway - keep up the great posts and even if ppl don't reply (I've not usually got much interesting stuff to say), just take note it is being read. Ciao babies