98 Jetta TDI speedo problem

willysrule

Member
Joined
Mar 16, 2008
Location
Lowber, PA
TDI
98 Jetta
I have a 1998 5-speed Jetta TDI...200K


the speedometer will go crazy sometimes...it will bounce as it climbs so high that it pegs out below 140 mph and stays there, even when slowing down or stopping...If I shut the car off the speedo will bounce on it's way back to zero and it will work fine after I start the car back up...the odometer seems to be counting fine when the speedo acts up...


I have ordered a speed sensor, waiting for it to come in...


TIA for any info you guys can toss out there...;)
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Sounds like the speedo itself. You may be heading for a cluster rebuild. Have you had alternator, battery or general low voltage problems recently?

Tony
 

willysrule

Member
Joined
Mar 16, 2008
Location
Lowber, PA
TDI
98 Jetta
TonyJetta said:
Sounds like the speedo itself. You may be heading for a cluster rebuild. Have you had alternator, battery or general low voltage problems recently?

Tony
nope, nothing with the voltage... it runs fine when the speedo is ok or acting up...I can shut the car off and the speedo usually bounces back to zero and then if fine again...
 

apecar

Well-known member
Joined
Feb 22, 2004
Location
Kingston, ON
TDI
1998 Jetta
I had a similar trouble a couple of years back. It turned out to be just a bad ground. Of course, I found this out after replacing the speed sensor, then the instrument cluster...
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Grounds are always a good place to start if you've never cleaned them. Can't hurt, and you may find some surprises.
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
willysrule said:
I have a 1998 5-speed Jetta TDI...200K


the speedometer will go crazy sometimes...it will bounce as it climbs so high that it pegs out below 140 mph and stays there, even when slowing down or stopping...If I shut the car off the speedo will bounce on it's way back to zero and it will work fine after I start the car back up...the odometer seems to be counting fine when the speedo acts up...


I have ordered a speed sensor, waiting for it to come in...


TIA for any info you guys can toss out there...;)

hey, whered u order your part from? I can only seem to find ones for auto trannies but I dont know if its the same for all models. I pretty much narrowed my problem down i think. I put the cluster in the diagnostic mode and the VSS signal goes to zero when the speedo acts up.
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
yeah...TDIjetta99 checked it when i had my car in the shop for injectors on Friday..

i just ordered the replacement
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
yeah...TDIjetta99 checked it when i had my car in the shop for injectors on Friday..

i just ordered the replacement.. its only $30
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
ok, so I swapped out the VSS last Thursday and it was fine for a few days until today. it did not work at all, same symptoms as before. I just got back from taking off the harness off the VSS and cleaning the connections. the connections are clean on the other side as its a new part.

so...still a malfunctioning speedo :confused:
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
i cleaned the wires around the VSS but didnt mess with the clump of wires it leads to where they all come together on the front of the motor. I changed the battery terminal less than a year ago so thats pretty squared away. i have not messed with any other grounds on the car..

where should i look besides those places? thanks for reply's...they are much appreciated.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
There are two (iirc) next to/under the battery and windshield washer reservoir. I think there's one near the ecu? Might not be remembering that one correctly, it could be that the ecu grounds through it's case. Make sure it's securely mounted. At least that's what I think I remember. Make sure the connector to the ecu is solid and no corrosion where it plugs in. Deoxit might be your friend in this situation.

Cleaning this stuff can't hurt, and there's about 1 in 100 chance that it'll help. I'd expect other odd problems with a bad ground.
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
rdkern said:
Cleaning this stuff can't hurt, and there's about 1 in 100 chance that it'll help. I'd expect other odd problems with a bad ground.
yeah, there are no other issues...i thought the new VSS would do it. they even feel different when turning the little thingie that sticks into the tranny end.



Chris Bell said:
ugh... funny, i cant find the little smiley face that is shooting himself in the head to express how i feel about messing with that clump!

i guess next step is check the grounds and clean that clump out... thx for the help
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '97 Passat sedan, '96 Passat variant
No clump-messing required. Check one of my posts in your other thread about this that locates the VSS ground (or narrows it down to two spots).

And whatever you do, do not, I repeat, do not read this post.
 
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1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
o yeah, i forgot about that post. well, its good i dont have to mess with the orb of death..

thx, ill report back how it turns out :)
 

1point9turbo

Veteran Member
Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
wow. so i decide to pop the hood before i left work to see if i couldnt find the ground (the one you mentioned in the other thread i have) and when i traced the wires and found where it was, i was pretty shocked to see that the brown/green wire completely rusted out of its connection to the ground. the other brown/white and whatever the other one is are connected.

so, you mentioned the brown/green being the ECT i believe...next question, what is the ECT? because apparently it hasnt been grounded for a while! im going down now to mess with them and redo the grounds in the area.

Ill take some pictures...
 

1point9turbo

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Joined
Oct 5, 2004
Location
Wichita, KS
TDI
1998 Jetta TDi Black
yes, i figured that out when i rested my hand on the hose and it was hot lol. thanks for the help! i mistook the brown/green wire that rusted off...it was actually the brown/green from the VSS.

turns out there are two brown/green wires that go to the same ground point, one comes from the ECT and the other VSS.

Just for anyone who is searching or may have a problem, check this area...

here is area with the wire cluster and underneath where the ground is...


now, a labeled one...


here is a close up of the broken connections...check here if you are having an issue with your speedo...


and the broken piece...



I didnt take any of the fix or after i was done but i basically used the same type of connector. strip the wire about a quarter of an inch and used a crimp connector (i hate these but i didnt feel like soldering).

Next, checked the other ones and they were solid. cleaned them with terminal cleaner and wire brush.

Next, put some vaseline over the screw, the nut and the 3 connections to slow the corrosion a bit.

Then, tightened the bolt on the end and made sure they were all tight to each other.


Chris Bell is the man, nailed it right on the head...only i bought a new VSS first before following his advice and finding this ground. Thanks, Chris. O well, now there is a nice clean connection and a new VSS.


hope this helps if someone else is having a problem. ..and yes the speedo is working... i only went about 2 feet in the parking spot i was in but it did move. it hasnt moved since about 2 weeks ago
 
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jw5714

Member
Joined
Jul 11, 2011
Location
Highland IL
TDI
98 Jetta TDI
Ive been using a gps since i got the car 4 months ago. i'm glad i ran into this forum... speedometer and cruise works like a champ..... Thank you!!!!
 

KS97Passat

Veteran Member
Joined
Mar 7, 2005
Location
Norwich, KS
TDI
Passat sedan, 1997, maroon, 129k mi.
This thread helped me to fix the speedometer/odometer of a rust-bucket from New England I just bought! The terminal of the sensor on my car had the same problem. It's just a little shocking that the ground wire terminations are not protected from corrosion.
 

wa4moe

Member
Joined
Nov 30, 2012
Location
Waxhaw NC
TDI
1998 Jetta
'98 Jetta TDI manual, AHU. Had intermittent speedo. New sending unit installed. Sent cluster in for repair; Came back with note- all working correctly, no charge.
Re-installed cluster. Checked, no codes, cruise control working, clutch working, brake working. All systems go.

Now where do I look and start for further diagnosis?????

Any help appreciated. TNX
 
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Jetta SS

Veteran Member
Joined
Oct 30, 2006
Location
Grand Bay, AL
TDI
'98 Jetta
I've been without for a few years now. New sending unit, cluster checked out, all exposed wiring inspected. Think my problem is under the dash somewhere. Thing works about 50% of the time. One of these days I'll pull the dash - till then I'll use the gps.
 
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