Glow plugs issue

Westwindmk3

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Nov 26, 2019
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MkIII 110 1996
Hello everybody,
My car is golf 3 1996 TDI.
The problem is that the glow plugs indicator isn't showing on the cluster, no voltage on the wires to the plugs either. I measured current between 87 and 30, it's ok 12.5v. I measured 86 power from ignition is also present, 85 is about 6volts coming from the ECU. Fuse is also OK.
I'm really confused at this point. Are there any other components that interfere in the preheating system apart from the coolant sensor? I haven't measured continuity of wires from the relay to the plugs. that's the last thing I could go further with my knowledge.
Any other suggestions will be really appreciated.
Thanks.
 

Mongler98

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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
i just saw a thread recently where its just a matter of getting the multimeter on really fast, something about voltage dropping really quickly.
 

Vince Waldon

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2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Find the fantastic multi-page "Glow Plugs 101 V2" thread and read read read..... lots of great info, pictures, etc.
 

Westwindmk3

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Nov 26, 2019
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Morocco
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MkIII 110 1996
I tested all again, this time everything works as it is supposed to apart from the indicator light in the cluster. I'm sure that there is no problem in the cluster or the glow plugs bulb. Is the waiting period plug light controlled by the ecu or the relay?
 

Mongler98

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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I tested all again, this time everything works as it is supposed to apart from the indicator light in the cluster. I'm sure that there is no problem in the cluster or the glow plugs bulb. Is the waiting period plug light controlled by the ecu or the relay?
it is, via the MAP program in the ECU, it can be set with VCDS to longer or shorter. (i think) or it has to be done with a tune, If i remember correctly, its done with VCDS.
you sure the bulb is still good???? its nearly a 30 year old car!!!
 

garciapiano

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1997 Jetta TDI (1Z)
if the glow plug lamp doesn't come on briefly in the dash upon first key-on, your bulb is out. If the bulb is out you will also get a code stored for glow plug indicator lamp open circuit.

One way to test if the glow plugs are actually cycling is to disconnect the coolant temp sensor harness plug from the sensor located on the outlet flange (NOT the A/C temp switch on the upper radiator hose). If the coolant sensor is not detected by the ECU it will cycle the glow plugs for the maximum duration, with the corresponding light on in the dash.
 
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Westwindmk3

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Nov 26, 2019
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Morocco
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MkIII 110 1996
it is, via the MAP program in the ECU, it can be set with VCDS to longer or shorter. (i think) or it has to be done with a tune, If i remember correctly, its done with VCDS.
you sure the bulb is still good???? its nearly a 30 year old car!!!
I'm sure the bulb is good. I run 12v to its wire in the cluster and it goes on. So no problem with the bulb, it's not getting any signal logically.
 

Westwindmk3

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MkIII 110 1996
if the glow plug lamp doesn't come on briefly in the dash upon first key-on, your bulb is out. If the bulb is out you will also get a code stored for glow plug indicator lamp open circuit.

One way to test if the glow plugs are actually cycling is to disconnect the coolant temp sensor harness plug from the sensor located on the outlet flange (NOT the A/C temp switch on the upper radiator hose). If the coolant sensor is not detected by the ECU it will cycle the glow plugs for the maximum duration, with the corresponding light on in the dash.
When I disconnect the temp sensor, the relay kicks and cuts very quickly, a second or less. The bulb is not on either.
I guess there are two seperate problems after this test. One with the bulb not coming on in all conditions, and one with the glow plugs relay cutting off this quickly after removing the temp plug sensor as it should stay for a longer period as you said.
The previous owner has really been messing with the car electronics.
 

Westwindmk3

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Morocco
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MkIII 110 1996
What are the fault codes, if any?
Unfortunately, I can't reach an obd at the moment to scan for codes.
There is an update. I figure out the issue of the glow plugs lamp, it was a cut wire from the relay/fuse panel on U2 connector to the cluster. Now the lamp goes on but goes off in a second. I disconnect the CTS plug and the lamp stays on for about 20 seconds. This led me to measured the CTS resistance, the output was between 750 oums and 1700 oums. I'm not sure if this is within the specs. I think I'm getting closer. There is another issue, there is grey smoke even when the engine is warm. Can a bad CTS be the cause of the smoke?
Glow plug lamp flashing after engine starts.
 
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Vince Waldon

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You really really need to scan for codes... really. :)

The flashing glow plug light is a "fix me ASAP" CEL and there will be one or more codes that will point you in exactly the right direction.

20+ reasons for a flashing glowplug light, only a couple related to the actual glow plug system.
 

Westwindmk3

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Morocco
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MkIII 110 1996
You really really need to scan for codes... really. :)
The flashing glow plug light is a "fix me ASAP" CEL and there will be one or more codes that will point you in exactly the right direction.
20+ reasons for a flashing glowplug light, only a couple related to the actual glow plug system.
I'll try to scan for codes and come back for update.
Thanks friends
 

Westwindmk3

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Location
Morocco
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MkIII 110 1996
Neither Delphi nor Vcds couldn't communicate to the car, connection fail. This is an unexpected problem which i need to figure out first. While the scan tries to connect to the ecu i can hear some klicks. Pin 7(ground) ok. Pin 16(+12) ok, the adapter comes on, so i need to check the K line and L line but I'm not sure if they are going to the ecu without briges.
 

Westwindmk3

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Nov 26, 2019
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Morocco
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MkIII 110 1996
I figure out this morning that pin 7 for K line is connected to the immo box which the source of the klicks when the adapter tries to connect with car. Pins 4 and 6 for groung are cut from immo box, i'm not sure if the imo box prevents the adapter to communicate with ecu because of the cut wires. This car really drives me mad. I would mention that the immobaliser is disabled in the car since it can starts with a normal key without a chip. I'm not sure how they did so.
Any ideas please!
 

Steve Addy

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97 Mk3
First I'm unclear why the ground wires would be cut from the immo box but you either need to reconnect those or bypass the immo and ground directly.

Grounds should be brown, is the other wire red with white stripe? Can you tell where that wire goes into and out of the immo module?

Since we didn't get that module here in the US it's hard to know how it was implemented, but the goal is to route wiring around that module if there's a problem with it.

And yes, you need to first get the ECU communication restored so you know what, if any, codes are being stored.

Steve
 

CasaEd

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There's a connection block on the steering column that the K-line & L-line connect into,
The K-line is pin 61 in the ecu plug, so just check continuity between the ECU plug & the OBD plug, if need be just bypass the immo box to see if you can then communicate with the ECU.
 

Westwindmk3

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Morocco
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MkIII 110 1996
First I'm unclear why the ground wires would be cut from the immo box but you either need to reconnect those or bypass the immo and ground directly.

Grounds should be brown, is the other wire red with white stripe? Can you tell where that wire goes into and out of the immo module?

Since we didn't get that module here in the US it's hard to know how it was implemented, but the goal is to route wiring around that module if there's a problem with it.

And yes, you need to first get the ECU communication restored so you know what, if any, codes are being stored.

Steve
You're right, the cut wire are both brown and both ground. I tried to ground them both, still no connection. I'm thinking of bypassing the immo as you said, but i don't know how. Can I connect the K line (grey/white) from the obd port to the other coming from the ecu without the immo in between?
 

Steve Addy

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Iowa
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97 Mk3
You're right, the cut wire are both brown and both ground. I tried to ground them both, still no connection. I'm thinking of bypassing the immo as you said, but i don't know how. Can I connect the K line (grey/white) from the obd port to the other coming from the ecu without the immo in between?
You can try and bypass the module, the grey/white wire to ECU pin 61 should go to a junction block somewhere. My notes on the wiring say, "double connector, on (TV14)DLC wire connector, behind console. Mk3 says to T1y (no destination) dashed lines (AT only?)" from when I built my B3V harness.

The problem might be if the immo is controling power to the ECU and then it won't matter if you bypass the immo module or not.

I would first like to see a picture of your immo module and the especially the wiring going to it.

Oh and CasaEd, isn't the L-line just a dead end on these? IIRC my L-line wire went to a junction block and that was it, no connection to anything else.

Steve
 

Westwindmk3

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Morocco
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MkIII 110 1996
You can try and bypass the module, the grey/white wire to ECU pin 61 should go to a junction block somewhere. My notes on the wiring say, "double connector, on (TV14)DLC wire connector, behind console. Mk3 says to T1y (no destination) dashed lines (AT only?)" from when I built my B3V harness.
The problem might be if the immo is controling power to the ECU and then it won't matter if you bypass the immo module or not.
I would first like to see a picture of your immo module and the especially the wiring going to it.
Oh and CasaEd, isn't the L-line just a dead end on these? IIRC my L-line wire went to a junction block and that was it, no connection to anything else.
Steve
I tried to bypass the immo. First, I checked continuity from pin 61 on the ecu and the 3 grey/white wires on the junction box above relay/fuse panel, no continuity in all wires. I run a wire directly from pin 61 to the obd2 port, still no communication.
Wires on the junction box above fuse/relay panel are as follows:
Yellow and grey/white coming from the obd port (yellow plug)
Grey coming from immo pin 3 (brown plug)
Grey/white coming from immo pin 2 (black plug)
Grey/white I think coming from the ecu. Not sure. (Grey plug)
Light grey/white (blue plug) not sure from where it's coming
A black wire coming from the immo pin 1 not coming to the junction box, I couldn't trace it. I think it goes to the ecu. Not sure again.
I have the photos, but i'm not sure how to post them.
 
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Westwindmk3

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MkIII 110 1996
Update
After checking the following link I figured out my assumptions was wrong concerning the wires and where they runs.
http://www.vwforum.nl/how-to-immo-startblokkering-wfs-ecu-inleren-150605
I'll have to recheck the connections based on the description in the link.
The only thing i still need is how to bypass the immo since it's no use for the car to start and made a connection directly to the ecu, abs, airbag.

the immo 5 pins plug:

1 = Black> Switched +
2 = Gray / White> To ECU
3 = Gray> K-Line to be read out (To distribution block)
4 = Brown> Ground
6 = Brown> Mass
 
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Steve Addy

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Iowa
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97 Mk3
That's interesting, so the 1) black is circuit 15, 2) is the K-line wire TO the ECU and 3) is the K-line from the immo to distribution block?

I'm not sure how it's stopping the car from starting if these are the only connections? I was under the impression that grey/white to pin 61 was for data link although I suppose it could be used as a disabling feature, I'm just not that familiar with it.

As a 1996 car it must be VW Immo generation 1, which I thought was pretty simple. Is there any way you can provide a vw part number off the box? It would help if I could see what you were dealing with.

Thanks
Steve A
 

Steve Addy

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97 Mk3
I stumbled upon this thread, it talks just a little about Immo that sounds about like yours. I'm dropping this here so that it doesn't get lost and I can't find it later....that has happened before.

The wiring diagram he's created sounds similar to your situation although his box has a transponder ring?

Steve
 

Steve Addy

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97 Mk3
I remember now this issue came up with another member here who owns a B4 sedan that's being restored. I'm not sure but that user might have gone with a immo emulator product to bypass their failed module.

Anyway, here's some more info I dug up about it.

I have also read that there is a chip on the ECU for this too that needs to be dealt with but I cannot verify that this applies to your car.

Steve
 

Westwindmk3

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Morocco
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MkIII 110 1996
That's interesting, so the 1) black is circuit 15, 2) is the K-line wire TO the ECU and 3) is the K-line from the immo to distribution block?

I'm not sure how it's stopping the car from starting if these are the only connections? I was under the impression that grey/white to pin 61 was for data link although I suppose it could be used as a disabling feature, I'm just not that familiar with it.

As a 1996 car it must be VW Immo generation 1, which I thought was pretty simple. Is there any way you can provide a vw part number off the box? It would help if I could see what you were dealing with.

Thanks
Steve A
This is the part number of the immo
1h0 953 257 bb Siemens 5WK4 678
 

Steve Addy

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97 Mk3
This is the part number of the immo
1h0 953 257 bb Siemens 5WK4 678
This PDF has some extra information and wiring diagram for you module.

Since it's about their immo emulator it doesn't tell you much about how to correct without buying their product, but it gets us closer to a resolution.

I have a suspicion that this immo box talks to a separate chip in the ECU, otherwise a person would only have to unplug it and bypass it to get the car started again.

In the UK link about the ABF engine there was talk about the chip in the ECU but I'm not sure if that applies to the AFN cars.

I know that member lisab4 had to buy an emulator to get around this problem. I've been hoping that they would chime in about this.

Steve
 

Westwindmk3

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MkIII 110 1996
So as to recapitulate and clear up things.
The cars starts fine and goes fine without issues whether the immo is connected or not. This means that the immo was bypassed somehow letting the car starts without a key chip.
The problem now in focus is why the car doesn't communicate on the OBD.
These are the things I've checked and done:
Measured continuity btw ecu pin 61 and pin 2 to the immo OK
Measured continuity between pin 3 from the immo to the distribution box above relay/fuse panel OK
Measured continuity btw k line from obd port to the distribution box OK
Measured voltage on K line (on obd port) with the immo plugged 11.5v. with the immo unplugged meaning measuring voltage from pin 61 on the ecu directly 8.3v
Tried to bypass the immo by joining immo pin 2 and 3 in the immo plug to communicate directly with ecu NOTHING
Tried to unplug all other wires from the distribution box above fuse/relay panel leaving the K line + the L line (from the obd port), and the K line coming from the immo plug 3. Assuming that other modules like abs and airbag may interrupt the connection in any way.

I'm stuck at this point.
 

Westwindmk3

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This PDF
I have a suspicion that this immo box talks to a separate chip in the ECU, otherwise a person would only have to unplug it and bypass it to get the car started again.
In the UK link about the ABF engine there was talk about the chip in the ECU but I'm not sure if that applies to the AFN cars.
I know that member lisab4 had to buy an emulator to get around this problem. I've been hoping that they would chime in about this.
Steve
I agree with you, but the wires are clear about what the immo does. 3 wires coming from the key reader on the ignition switch and the 5 other wires: 4 and 6 ground, 1for +12, 2 k line from ecu, 3 k line to the distribution box above relay panel. Shouldn't be another one communicates to the ecu or the ignition circuit to stop the car from starting? Bearing in mind that the K line coming from pin 61 on the ecu is signal wire for reading data out of the ecu, how does the ecu reads out of the immo or receives signal from it?
 

Steve Addy

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Iowa
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97 Mk3
I agree with you, but the wires are clear about what the immo does. 3 wires coming from the key reader on the ignition switch and the 5 other wires: 4 and 6 ground, 1for +12, 2 k line from ecu, 3 k line to the distribution box above relay panel. Shouldn't be another one communicates to the ecu or the ignition circuit to stop the car from starting? Bearing in mind that the K line coming from pin 61 on the ecu is signal wire for reading data out of the ecu, how does the ecu reads out of the immo or receives signal from it?
Well that's not entirely true, we know that VCDS communicates with and allows changes in the ECU settings via pin 61 so it's not just data receipt, it's a two way street.

As I said, I'm not at all familiar with the workings of these but just what I was able to ascertain from others posting up about dealing with them. If in fact your ECU has a separate chip for dealing with the IMMO, which I believe it probably does, then maybe the only way to deal with this is with a emulator that others have purchased.

Steve
 

Westwindmk3

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MkIII 110 1996
Well that's not entirely true, we know that VCDS communicates with and allows changes in the ECU settings via pin 61 so it's not just data receipt, it's a two way street.
As I said, I'm not at all familiar with the workings of these but just what I was able to ascertain from others posting up about dealing with them. If in fact your ECU has a separate chip for dealing with the IMMO, which I believe it probably does, then maybe the only way to deal with this is with a emulator that others have purchased.
Steve
How idiot I was thinking pin 61 is a one-way signal. Thanks Steve for raising this. One more inquiry is what will the emulator do for my obd being not responsive. To my knowledge, which i hope is also false, an emulator is installed to bypass the immo so as to be able to start the car without a chip in the key. In other wards, how can the emulator help me connect to the ecu?
 

CasaEd

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If the car starts and runs you do not have an immo fault, if the car was to start then cut out straight away or not start at all then you would have a immo issue, the chip is in the ECU and can be de-soldered and read in a eprom reader to have it's immo off.
Fitting an emulator will not cure an OBD fault, if you have checked all the wires for feeds and continuity and they check out, then it might be possible the fault is the actual ECU itself, or the VCDS lead you are using. If you have access to another ECU or vehicle with the same 68 pin plug trying swapping things around and see what you come up with
 
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