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Discussion Starter · #1 ·
So it seems i've resolved my problem in the other thread, and now i'm stuck on a speedo problem. When i start the car and get going the speedo works normally up to about 40km/h, and then it starts bouncing around and generally stays that way the rest of the drive. Although it will stop when the car stops, but even then its sometimes going wonkers.. i even noticed in one instance that it bounced when i revved the engine, but usually its doing its own thing.
The VSS down on the tranny seems perfectly fine visually.. and the odometer seems to roll normally as well, although on one day it actually did go slower than it should.
Does anyone have any tips on speedo repair? I've had it out completely but can't see any mechanical damage or anything out of the ordinary...
 

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Discussion Starter · #2 · (Edited)

i found this for a good price here in europe, and i believe that it doesn't matter that its for a 2.0.. mine is the 2.5, and i can always just use the speedo itself if the cluster isn't compatible.
In any case guys, let me know if you think it could be a wiring issue considering the above symptoms.. i will have a look at that as well just in case although it seems logical that if the odometer is working that the needle assembly itself is out of order.

btw.. no codes thrown either..
 

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Rectangle Schematic Font Slope Parallel

On my 2001 the VSS signal goes to the PCM, cruise control and speedometer.


Electrical wiring Electronic engineering Computer hardware Cable Electrical supply

I can back-probe the PCM connector to get access to the VSS signal.

Automotive lighting Electronic instrument Light-emitting diode Audio equipment Gas

I usually get the chassis ground from the DLC connector.

Slope Font Parallel Technology Pattern

With a scope at 30 MPH (48 KPH) I recorded a 34 Hz pulse train coming from the VSS.

Gadget Audio equipment Font Input device Electronic device

If you don't have a scope, an AC voltmeter with a frequency option will also work.

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At 30 MPH the voltmeter was also reading around 34 Hz. You might want to check the VSS signal
before you spend 65 euros on an instrument cluster.
 

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Discussion Starter · #4 ·
great info! i will certainly give that a try tomorrow with my multimeter. 🤟
 

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Discussion Starter · #6 · (Edited)
yep, wishful thinking, i was convinced my dmm had that option.. next stop, try the one at work, nope.. next stop, buddys place tomorrow...
 

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Discussion Starter · #8 ·
i just reduced my post, just saw that i probed the wrong pin.. arrgh.. again tomorrow...
 

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Discussion Starter · #10 ·
4wd, manual 2.5 V6. I was in a bit of a hurry and connected the probe to an empty pin. There are 3 connectors on the ecu, and according to the service manual pin #2 is the vss.. the rightmost connector is the only one where #2 is connected, but i in a rush connected the empty #2 pin on the middle connector 🤦🏻‍♂️. Maybe all #2 pins are connected within the ecu so i got a proper reading anyways, i dont know, but i guess to be sure its best to repeat tomorrow.
 

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Discussion Starter · #11 ·
aaand now when ive had a chance to sit down properly, i see that i was looking at the pinout for the auto transmission version ecu.. totally buggered up today.
 

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Discussion Starter · #13 ·
So, first mistake i made being in a hurry is searching the 1of2 service manual where there us minimal info on the vehicle speed sensor.. service manual 2of2 has everything.

Font Parallel Screenshot Number Document


With this test i had voltages everywhere in between, not only as suggested above.

Font Parallel Pattern Number Document


Here at step number 3 i had just over 12v, and at step number 4 i had 10v. This is all pointing to a faulty VSS. Next to that i tried your test with the frequency and got steadily rising frequency as i got up to speed slowly and while the speedo wasn't jumping, and as soon as it started to jump the frequency readout went haywire as well.

I suppose the last thing i can try is try the frequency test again but with the speedo coupler disconnected to make sure that its not screwing with the system, possibly introducing interference.
 

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Discussion Starter · #15 ·
No cruise control in my car.. but, that doesn't matter anymore.

In continuation.. after all the testing today, i went under the car again and followed the vss cable up into the engine bay, looked at what i could see and felt up what i couldn't. The wiring seemed ok other than the fact that it wasnt fixed against the firewall but rather laying against the engine. So i moved it away and decided to have a look another day and clean all that up a bit.
Later in the evening when i got in the car again, voila, speedo works just fine. So, obviously it was a wiring issue.
Now its just a question of wether there is a damaged wire, or maybe just the wire being right against the engine creates intereference in the signal 🤔🤔
 
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