TDI starter not turning (ideas needed)

[VChristian]

After not driving one of the 2002 TDIs, I started it up, and found that the ignition switch was intermittent, or so I thought.

Today the intermittent switch became a hard failure. So I did what most people would do...replaced the switch. After nearly 20 years and over 300k miles, I figured that made sense. So the old switch went out, and a new one in.

But that didn't do the trick.

In the morning I will hook up VDCS and try to find out what is going on. The bugs are a bit too thirsty tonight.

Since this is not the normal "my car won't start" I thought I would post for any ideas.

When the problem was intermittent, I would wiggle the key, usually putting the inside "down" and that would get it going. I have probably started it 25 times that way. Until today.

 

[Tdijarhead]

Two things come to mind.

Does this mean your car cranks and cranks and doesn’t start and the glow plug light doesn’t come on? Replace the 109 relay.


Or you turn the switch the dash lights up but nothing else? Since your in the ny rust belt check the fat copper wire on the top of your starter, it’s about 2” long and turns to dust in our fair climate.

 

[VChristian]

No, it will not attempt to crank at all.

When intermittent, wiggling the switch got it to fire. I checked out the starter earlier before I found that the ignition switch wiggle worked.

Of course, now, no wiggle works.

But I can bump start the car, and all the electrical is normal.

 

[csstevej]

Clutch switch intermittent?
Dead spot on the starter?
Any click when key turned to start?
With someone turning the key to start try tapping starter with a hammer?
Ground to starter good?

 

[VChristian]

Clutch switch intermittent?
Dead spot on the starter?
Any click when key turned to start?
With someone turning the key to start try tapping starter with a hammer?
Ground to starter good?

When the problem was intermittent, the clutch switch was the first thing I looked at, and VDCS reported it consistent with my operating the pedal.

When turning the key to start, there is a very faint click, and it is not at the starter. I think it is in the accessory area, like for killing fans, etc.

The starter solenoid does not appear to be the problem. I went after that early in the game, and it was working OK. The ground was good, and when things got working, I did a quick current/voltage check and all looked good.

No relevant codes.

I think there is a place in VDCS where I can look at the ignition switch, and I will be doing that in the morning. Any other suggestions, I can chase after are welcome.

Thanks.

 

[4Gman]

I would second that 109 relay. It's cheap and if it's the wrong color it's goin' wrong soon. Should be gray not black....I think...can someone confirm.

 

[Tdijarhead]

Gray is correct. How is that fuse panel on top of the battery? They are noted for melting.

 

[WildChild80]

Pull the connector off the top and see if you're getting voltage there in the start position as in is it getting a start signal to the starter, if it does, get some jumper cables and connect to the lug on the starter and hit the key(the one that the hot lead goes to, not the motor lug)

Voltage and current are different animals...you could also put your multimeter to ohms and touch the engine and your negative terminal and see how much resistance you have

Sent from my Pixel XL using Tapatalk

 

[VChristian]

The cables off the battery are low resistance. There are no problems with start current, when the problem was intermittent.

The top fuse box on the battery buzzes out good.

I swapped a 109 relay in this morning, and it did not change anything. I believe the 109 relay is a load relay and is not used for starting. If it were defecting, I would except that other things would not be working.

I am looking now to see if there are any other lockout switches, other than the clutch switch, which would prevent starting.

 

[sniderbm]

have you taken the starter off and had it tested, not just test the electrical to it?

my b4 passat (240k) went from consistently starting well and 1 time out of 5 having the starter just not quite give it 100% (would spin motor for 4 seconds before starting instead of 1 and only about 3/4 speed) to doing nothing in a matter of days. It made sounds like you're describing (faint ish click) but just lost the muscle to spin the motor. 1 time in 20 I'd get a very slight grunt from it like the starter moved it 1/8th of a turn or something.

Tried jumper cables, nothing.

Towed it home and pulled starter, took to parts store and it spun on their test bench 1 time out of 3. New starter and it spins better than anything I own.

 

[oilhammer]

So much misinformation in this thread.

You can take the relay 109 out and throw it in the trash, the engine will still crank. That relay has ZERO to do with the starter getting a signal to crank the engine.

Ignition switches rarely fail. It is more common, especially on NBs, to see the connector to the switch get crunchy and deform.

The CCM has the ability to halt starter signal due to anti-theft function. AKA: the alarm system. And no, this is NOT part of nor has anything at all to do with the immobiliser.

You need to see if the voltage is coming OUT of the ignition switch on the proper wire when the key is turned to the crank position. You will need a wiring diagram. I would also check the J207 starter interlock relay.

 

[VChristian]

Apparently the Bently wiring diagrams differ from third party published wiring diagrams.

Here's my understanding thus far:
-the starter switch has been replaced, and the old 300kmile+ one appears to be OK, but some of the contacts have less spring than I would expect.
-the connector to the starter switch is in good condition, and the plastic is not brittle.
-the clutch switch is good by VDCS
-there is apparently an anti-theft relay after the clutch switch

The problem is not the starter, and a jumper to the solenoid will get action every time.
The problem is not a power distribution problem, in that the starter, battery and cables are working well.

Right now, I am going after the clutch switch, because I believe it may be a double pole switch to permit starter blocking and also cruise function.

 

[oilhammer]

There are two clutch pedal switches. One is just at the top, and is for the ECU. The other, at the bottom of the travel, is for the starter lock out. The ECU does not care about the latter.

The J207 relay is in the relay panel inside the car, above the pedal area, position 3, it most likely has a '53' on it, because it is a common relay used in various places.

 

[VChristian]

Yes, I just found out that there is a clutch switch, and a clutch position sensor. The latter feeds the ECU (which I was looking at) and the former is used for the starter.

After I cool off and do some work inside, I will head out, and get my hands on the clutch switch and check it's operation.

 

[VChristian]

OK, fixed, and starting reliably. Here's a summary of what I did and what I found:

-since wiggling the ignition switch got it to start, I assumed there was a switch problem. There was not, but now I have a new switch. $50, probably not well spent.

-started following the circuit. Be careful around the clutch switch. There is a clutch position switch (used for cruise) which you may wish to avoid removing. Apparently the new ones cannot be reset and reinstalled. The clutch switch used for starting, is the one on top of the clutch pedal assembly. It was working OK. Oh, VDCS only shows the clutch position switch, which is not relevant in a starting issue.

-Went to J207, the relay in the third position of the aux relay layout. "53" on it. Took it apart. After almost 20 years and 300k miles, it had a little pitting on one of the contacts. 1200 wet/dry and put it back in. Then the starter was engaging. But not every time. 38 times out of 50 to be exact.

-So I went under the hood again, and jumped the starter to the + battery terminal. The arc suggested that the solenoid was not drawing the power I am accustomed to seeing. Did the jump several times, and found it missed once. So I swapped out the original starter. Put a reman in, and everything works every time.

I also ordered a new "53" relay to replace the one that I cleaned up the contacts on.

Case closed. Thanks for the inputs!

 

[oilhammer]

Thanks for following up.

I cannot recall ever seeing the J207 fail, if I have I simply do not remember. Bosch starters rarely die in a "no crank" way, they usually just get to cranking really slow.

 

[VChristian]

Thanks for following up.
I cannot recall ever seeing the J207 fail, if I have I simply do not remember. Bosch starters rarely die in a "no crank" way, they usually just get to cranking really slow.

The crank speed was OK when it worked. I think the coil in the solenoid got compromised, and with intermittently less current flow, it simply wasn't closing the contacts within the solenoid. It did not click when it was not engaging.

The relay replacement is probably not needed, but they are inexpensive, and I will probably not install the new one, just keep it in the glovebox for when I have the dash opened up again.

I don't have a good estimate of the number of starts on the engine, but for original components, I was pretty happy. The starter is original, and the 54 relay appears to be.

 

[wonneber]

Glad you resolved it and posted the summary.
It may help others in the future.