Glow plug electrical fault

[JollyGiant]

I have read a few posts on here about this re-occuring problem but just want to double check some things.

Here is what i have tried.

Resistance in all glow plugs seem approx the same, 1.2ohms if i used the digi meter correctly.

All glow plugs glow when connected to 12v source.

All glow plug leads deliver 12v, i clipped in a light bulb i could see when i turned the keys. What i did notice was the light still glowed even when the glow plug light in the dash went out, it glowed about 10 secs longer.

The fault i keep getting is electrical circuit on glow plug 3.

Does anyone have an idea where the problem lies. The glow plugs are not oem, should i replace them with bosche ones? Does anyone think the harness is at fault?

I am hoping to partX my FR TDI for a cupra MK II soon so i would like to get it sorted or should i just clear the fault and plead ignorance if the warning happens at the seat garage?

Thanks for any advice.

 

[oldman]

what is the actual error thrown up by vag-com check?
also, any light on the dash at all?

is struggling to start in the cold?
one thing you could do is change the harness bridge and or the glow plugs.

 

[techie]

Is this a 150bhp PD yes?

Do you have small wires going to the glow plugs or a thick wire linking them all?

If its small wires then you could have knackered the heater plugs anyhow as they are 5v plugs not 12v, putting 12v to them kills them.

 

[JollyGiant]

My car is an 05 150pd, it has wires going individually to each plug. I think they must be 12v as the 12v light bulb certainly shone brightly.

I don't have any probs starting in the cold and i have the yellow engine light on. I can't remember the exact wording of the fault but it goes along the lines of intermittent electrical fault on glow plug circuit 3.

 

[truCido]

I've had a friend with this error and it turned out to just be a bit of dodgy wiring on his glow plug. He had the loom replaced and the error never came back!

 

[JollyGiant]

I've had a friend with this error and it turned out to just be a bit of dodgy wiring on his glow plug. He had the loom replaced and the error never came back!

Do you know how much it cost to get done.

 

[techie]

It could well be the wiring, but if you follow that back under the wiper scuttle just next to the pollen filter is the glow plug control unit, used to get quite a few issues with them.

 

[JollyGiant]

It could well be the wiring, but if you follow that back under the wiper scuttle just next to the pollen filter is the glow plug control unit, used to get quite a few issues with them.

I always seem to get power to the plugs though, i turned key on and of with light bulb attached quite a few times. I rember the fault occuring after i had a glow plug go dead so i replaced all 4 and then get this intermitent fault. May be worth buying original bosche ones.

 

[oldman]

your last one, is the nail we needed.
harness needs replacing, clear code and be happy.

had exact same issue.
changed plugs but error came back an no issues driving or starting even in winter. Change harness and all good.

many a thread in the tdi section, have come to conclusion that if the fault code appears 1of 2 things;
plugs or harness.
change plugs and code comes back about 3months later then change harness

 

[JollyGiant]

your last one, is the nail we needed.
harness needs replacing, clear code and be happy.

had exact same issue.
changed plugs but error came back an no issues driving or starting even in winter. Change harness and all good.

many a thread in the tdi section, have come to conclusion that if the fault code appears 1of 2 things;
plugs or harness.
change plugs and code comes back about 3months later then change harness

Can anyone give me the part number for the harness and where i can order it online from, don't really want to go to dealers as may be part exing car soon.

 

[truCido]

Can anyone give me the part number for the harness and where i can order it online from, don't really want to go to dealers as may be part exing car soon.

would think the harness is a dealer only part to be honest

 

[oldman]

sorry, would need to dig out old receipts but think was in region of £20.
again look through tdi section and you'll find a few threads with pointers on how to do the job as well.

 

[Muttley]

JollyGiant wrote

All glow plug leads deliver 12v, i clipped in a light bulb i could see when i turned the keys. What i did notice was the light still glowed even when the glow plug light in the dash went out, it glowed about 10 secs longer.

The glow plugs have two phases of operation, pre-starting glow and afterglow. The afterglow phase always occurs, and is a reduced power operation of the glow plugs to ease the starting stresses on a cold engine.

The glow plug control (The ECU in most cases) sets the power sent to the glow plugs by limiting the current. Presence of 12V alone is not infallible proof that the glow plugs are getting the right amount of power.

Like others, I think the harness is the most likely source of this fault.

 

[JollyGiant]

sorry, would need to dig out old receipts but think was in region of £20.
again look through tdi section and you'll find a few threads with pointers on how to do the job as well.

I have found the part no from a previous post, 038971220D and phoned up my nearest VW garage. They wouldn't sell me the part saying something about warranty and told me to go to seat garage. Don't really want to go to seat as may be part exing for another car soon. Where and who will sell me this part?

 

[oldman]

any vw, skoda or audi garage can supply this.
your local vw is being annoying more than anything.

could try, tps

 

[JollyGiant]

any vw, skoda or audi garage can supply this.
your local vw is being annoying more than anything.

could try, tps

Phoned another VW garage and they have ordered it. Pity other VW garage wouldn't order it as they were on way home from work, for the other one i have to drive past my home then back again.

 

[oldman]

Phoned another VW garage and they have ordered it. Pity other VW garage wouldn't order it as they were on way home from work, for the other one i have to drive past my home then back again.

that's garages being difficult for you.

 

[JollyGiant]

that's garages being difficult for you.

Just hope 038971220D is the right part no for the loom with 4 wires

 

[oldman]

just looked back over old receipts, that is what i have
038 971 220 D
038 971 220D
038971220D

19.64 each +VAT

is what i got for mine:
150PD ARL
all four in one loom with a plug on the end

(repeated as you never can tell how people will search for it)

 

[JollyGiant]

just looked back over old receipts, that is what i have
038 971 220 D
038 971 220D
038971220D

19.64 each +VAT

is what i got for mine:
150PD ARL
all four in one loom with a plug on the end

(repeated as you never can tell how people will search for it)

My car is an 05 FR 150PD not sure of the next 3 letters but i guess the loom would be the same as yours.