2001 Jetta TDI Fuel Solenoid no power

[LeeMK4]

Hi I’m having issues with my 2001 Jetta TDI. I was driving to work and it stalled out on me while I was getting coffee in the drive thru. I tried to restart it but it just cranks. So I have read several threads to try and troubleshoot.
Here is what I have done so far:
- replaced relay 109
- replaced the fuel filter, lines bled
- replaced the starter as it crapped out after cranking too much.
- the battery is about 3 weeks old.
- timing belt has about 75kms on it and looks good.
- if I run a wire from my battery positive to the solenoid it starts right up. I’m thinking about running a switch with a permanent wire but would prefer to figure out the real problem.
I would appreciate any help I’m trying to DIY so I don’t have to take it to the shop.

 

[Nevada_TDI]

How far back can you trace the wire? It is quite possible for wires of that age to fray and cause problems. Have you double/triple checked the entire fuse block?

 

[Vince Waldon]

Does the glow plug light come on briefly when you first turn the key to "ON"?

ECU fuse OK?

Assuming the above, a continuity check of the wire between the ECU socket and the fuel solenoid would be a good next step, as well as a close visual inspection of the ECU socket itself.

 

[LeeMK4]

How far back can you trace the wire? It is quite possible for wires of that age to fray and cause problems. Have you double/triple checked the entire fuse block?

The wiring to the firewall looks good from what I can see. I haven’t pulled every fuse just checked the with voltmeter

 

[Nevada_TDI]

Just to let you know the wires to my N75 did not show they were intermittently shorting they looked good from the top.
Just because you can have you tested the voltage at the N75?
Yes I know the N75 has a PWM driving it, but check the power to it on both the DC scale, and the AC scale. Pulse Width Modulation will some times show up as AC voltage.
It happened to me.

 

[LeeMK4]

Does the glow plug light come on briefly when you first turn the key to "ON"?

ECU fuse OK?

Assuming the above, a continuity check of the wire between the ECU socket and the fuel solenoid would be a good next step, as well as a close visual inspection of the ECU socket itself.

Glow plug light comes on for 10 seconds or so. Do you know roughly which one the ecu fuse is I have pulled them all they good. I’m crappy with electrical unfortunately

 

[LeeMK4]

Just to let you know the wires to my N75 did not show they were intermittently shorting they looked good from the top.
Just because you can have you tested the voltage at the N75?
Yes I know the N75 has a PWM driving it, but check the power to it on both the DC scale, and the AC scale. Pulse Width Modulation will some times show up as AC voltage.
It happened to me.

I will try sounds a bit over my head I will do some googling

 

[Vince Waldon]

Looks like the ECU is fuse 10... but if the glow plug light is coming on the ECU has power and the fuse is OK.

MK4 fuse list

www.jettajunkie.com

The physical wiring between the ECU and fuel shutoff solenoid is probably the next thing to check, multimeter set to "ohms" or "continuity".

 

[oilhammer]

Any DTCs?

 

[LeeMK4]

Any DTCs?

Sorry there is no port to use a code reader

 

[LeeMK4]

I separated the wiring harness and all they all are supply 0.5v or more depending on the line. So I’m thinking the harness to the fuel solenoid must have issues. Thoughts?

 

[Vince Waldon]

Unfortunately voltage readings don't tell you much in this situation, as a line could read some voltage but has a problem and should actually read higher.

Hence referencing the need to check for continuity... the actual resistance of the wire between the ECU and the fuel solenoid.

As a side question: Is this a stock Jetta or a swap of some kind? "No port for reading codes" (and the fact that this is the swap sub-forum) suggests this is actually a transplant or conversion of some kind?

If so, gonna be all that much harder to troubleshoot over the interwebs, since anything could have been done by whoever did the work.

 

[LeeMK4]

Unfortunately voltage readings don't tell you much in this situation, as a line could read some voltage but has a problem and should actually read higher.

Hence referencing the need to check for continuity... the actual resistance of the wire between the ECU and the fuel solenoid.

As a side question: Is this a stock Jetta or a swap of some kind? "No port for reading codes" (and the fact that this is the swap sub-forum) suggests this is actually a transplant or conversion of some kind?

If so, gonna be all that much harder to troubleshoot over the interwebs, since anything could have been done by whoever did the work.

Sorry I found the port I will have to find some one with a reader. I can’t believe I didn’t see it. There was an old remote start box fastened in front of it.

 

[Tdijarhead]

How far back can you trace the wire? It is quite possible for wires of that age to fray and cause problems. Have you double/triple checked the entire fuse block?

Did you check the fuse block on top of the battery? Not the fuse panel. That block is prone to melting issues and many have had to replace it with a new block.

Battery Fuse Box [OEM] (A4 Early)

Fuse panel box on top of the battery made by OEM VW. This panel holds the high amperage blade fuses. This fuse box can melt if any of the fuses are overloaded, most common with a faulty starter (th...

www.idparts.com

 

[LeeMK4]

Did you check the fuse block on top of the battery? Not the fuse panel. That block is prone to melting issues and many have had to replace it with a new block.

Battery Fuse Box [OEM] (A4 Early)

Fuse panel box on top of the battery made by OEM VW. This panel holds the high amperage blade fuses. This fuse box can melt if any of the fuses are overloaded, most common with a faulty starter (th...

www.idparts.com

Yes the box looks good no signs of over heating or wear

 

[oilhammer]

Your at about Step 20, but you skipped Step 1. Checking for DTCs.

 

[LeeMK4]

Your at about Step 20, but you skipped Step 1. Checking for DTCs.

Waiting to borrow one from a friend. There has been a check engine light on for 10+years but I will let you know what I find.

 

[oilhammer]

Wow, yeah, sometimes ignoring things for a decade is not wise. But it may not be related to the car quitting on you.

 

[LeeMK4]

Yeah I got the car from my in laws last fall as my father in law retired and I travel lots for work so I needed something to save fuel.

 

[LeeMK4]

Your at about Step 20, but you skipped Step 1. Checking for DTCs.

I tried running diagnostics using my friends monitor and I’m getting a communication error. So I’m not sure what’s up I tried it on my truck and it worked right of way

 

[oilhammer]

You'll want a VAG specific scan tool for anything useful.

 

[LeeMK4]

Got it going again I had 2 bad fuses. They looked fine but were not. Car is going fine again.

 

[Nevada_TDI]

Care to share which fuses were blown? Was one of the fuses #34?

 

[LeeMK4]

I had to change Relay 109, fuse 32 and 34.