Wiring question, 1Z TDI into 1990 Jetta

clyde

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Apr 8, 2000
Location
confluence, Snake/Clearwater
TDI
1998 Jetta, 1959 DeSoto with leopard-skin seat covers
Need to get the speed signal to pin 43 of the ECU. Have the signal, but the other end of the wire on pin 43 is a mystery. The Bentley shows the wire from pin 43 going to "Instrument Cluster System." No info about which pin on the inst cluster.

Checked continuity between the signal line (white-blue wire) from the VSS connector and ECU pin 43, found no connection.

Anyone located this wire? The information would make the project easier than tracing wires…

Thanks!
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Jun 20, 1998
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Sterling, Massachusetts. USA
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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
It goes to TV13, a junction point with at least one, perhaps as many as three, other conductors connected at that same location.
I that the B4 Bentley schematic sheet X104 for cruise control has the TV13 listed there, with three blue with white stripe wires, Find this bridge junction with some blue / white stripe wires and see if you've missed any others that should also be plugged into this bridge.

The three pin Vehicle Speed Sensor (Bentley calls it a "speedodometer", that'll help your self esteem).
Pin 3 is grounded.
Pin 2 goes into the factory relay block at connector G, pin 1, through the block's internal conductors and then out at connector U1, pin 11. From U1/11 it connects to the cluster in terminal 28, pin 27.
Pin 1 goes to a common power supply junction fed by the load reduction relay.

I don't see that the VSS connects to the ECU except for possibly through the instrument cluster as intermediary. VSS to TV13 to cluster to ECU?
 

vwmikel

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May 5, 2005
Location
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'94 Golf Sport TDI
I have my vss wire split and going to both the ECU and the cluster. The speed shows up in vag-com and my MK3 cluster also works fine with the MK4 vss. I recall you asking about the speedo cable/vss dilemma before. Did you give up on the MK2 cluster?
 

G60ING

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Aug 5, 2001
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MD
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No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
I was just chasing this wire last week. Its one of the loose wires coming from the engine harness. Its a single pin connector with a blue plug. Its a blue with white wire. You will need a W connector for your fuse box and I think its the w3 pin that you get the speed signal from and this it leads to a 4 wire TV13 wire junction that clips on to the fuse box and allows the engine harness blue/white wire from pin 43 to plug in.
 

e*clipse

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May 9, 2007
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Chico, CA
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Toyota TDI swap
Hmmm. That's odd. Perhaps newer harnesses are directly connected? I'm working on my harness right now and that wire (blue/white VSS) has continuity with pin 43 of the ECU.

My harness is about as stripped down as possible. There's no TV13 connector and I'm not using the fuse/relay box.

By the way, has anyone looked at the VSS signal? I would like to connect it to my Toyota VSS, which puts out a 0 > 12V square wave 4X per driveshaft revolution. What is the frequency and amplitude of the VW VSS per wheel revolution?
 

clyde

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Apr 8, 2000
Location
confluence, Snake/Clearwater
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1998 Jetta, 1959 DeSoto with leopard-skin seat covers
VWMikel, I didn't abandon the Mk2 cluster. I need the wire to take the speed signal from the sensor in the speedometer to the ECU—the speedo cable is in the transmission's VSS hole.

Did as G60ing said, connected the blue-white wire from ECU pin 43 to pin 1 of the W connector, and installed the four-wire harness from the cruise switch to the four-wire connector behind the connection box.

It SHOULD work, e*clipse, because in my harness (97 Jetta TDI) the blue white wire with the single connector goes directly to pin 43 of the ECU.

By the way, this TDI forum seems to have been impossible to reach quite often this week. What's up?
 

Hasenwerk

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1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
If you are looking for a VSS it is quite simple to get this with an A2 cluster. You need to find a three wire VSS from a Corrado or GTI with a MFA cluster. This will give you the correct square wave that the ECU is looking for and it is all "plug and play"
 

clyde

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Joined
Apr 8, 2000
Location
confluence, Snake/Clearwater
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1998 Jetta, 1959 DeSoto with leopard-skin seat covers
Fast Forward, it's interesting that only cars with MFA (Corrados, GLI, GTI) used the three-wire Hall effect speed sensor. Now that you mention it, the other Mk2 VWs I've seen use a two-wire inductive sensor also mounted in the speedo head. Except for the speed sensor, the cruise systems are the same in both instances.

Why different sensors? Cost?

In Mk2 cars the ECU has nothing to do with cruise—the vacuum motor and servo control throttle position manually.

Curious…
 

G60ING

Top Post Dawg
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Aug 5, 2001
Location
MD
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No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
clyde said:
In Mk2 cars the ECU has nothing to do with cruise—the vacuum motor and servo control throttle position manually.
This is how the cruise is on G60 Corrados are too. I think I have a spare 1990 cluster (1991-1992 G60s had the VSS on the transmission) that I took apart and I can grab this part for. I'm actually going to the shop to pick up a bunch of rado parts so I'll try and remember to grab this for you.
 

clyde

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Joined
Apr 8, 2000
Location
confluence, Snake/Clearwater
TDI
1998 Jetta, 1959 DeSoto with leopard-skin seat covers
Thanks for the kind offer, G60ING, but I don't need a Hall-effect sensor. Have plenty on hand.

Just commented on the difference. Never realized the dividing line is the MFA, as it seems to be.

But I'm curious why different sensors were used…
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
darn I was about to feel good for having stored a couple clusters in pieces. Oh well. In the future for anybody reading this feel free to contact me and hopefully I will still have them as opposed to having thrown them out.
 

Hasenwerk

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Joined
Nov 28, 2003
Location
Quesnel, BC
TDI
1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
clyde said:
Fast Forward, it's interesting that only cars with MFA (Corrados, GLI, GTI) used the three-wire Hall effect speed sensor. Now that you mention it, the other Mk2 VWs I've seen use a two-wire inductive sensor also mounted in the speedo head. Except for the speed sensor, the cruise systems are the same in both instances.

Why different sensors? Cost?

In Mk2 cars the ECU has nothing to do with cruise—the vacuum motor and servo control throttle position manually.

Curious…
The two wire produces a sine wave and the three wire produces a square wave that is compatible with the TDI ECU and the TDI Instrument cluster. When I did Vanagon conversions, this is what I used for the VSS signal for the ECU - others have used the original speedometer tucked away with this VSS installed to control a MK-IV instrument cluster.

FYI The MK-4 clusters want one pulse per meter, which is perfect for the Vanagon Syncro and almost perfect for the A2 (950 pulses per KM).
 

Chelsea

Member
Joined
Aug 4, 2001
Location
Bedford England
Speedo Problem !!!

Can anyone offer some advice:-


1999myr Golf mk4 manual speedo n/w.


1).Have replaced speedo sensor, tested wiring at sensor got +12v ign and 0V GND ok.
2). Removed cluster assy sent for test and repair..with cluster out carried out a continuity test between signal wire at sensor and the multiplug at the cluster (BLUE WHITE wire CONTINUITY is ok)..........they bench tested and found it functioned ok no fault found,,,,sent it back with a note saying leave aux position on half hour before switching to FULL ign, carried this out ..............Road test still no speedo !!! Connected up VCDS and tested speedo function (needle went full scale and returned to reset position OK)..confirms stepper mtr is ok .



3) Fault code is impausable signal in INSTRUMENT TEST area,???????????

4). Cannot get the login code as my VAG-TACHO only reads clusters up to 1997myr !!!
5). If i can get the login does the software allow a more in depth diagnosis of the circuit ?,,,,,,when i carried out a VAG scope road test it flat lined no response..............i thought about getting a normal scope and testing for a signal on the BLUE WHITE wire at the cluster (the output from the speedo sensor to the cluster)......i am not sure if this possible (is it a over the CAN BUS or a square wave signal direct to cluster ?..I don't have a bentley maunal ...does anyone have a copy of the circuit from sensor to cluster ?)........or is it a PWM signal ?

Is there something obvious i am missing ?
Any help on this would be much appreciated

Regards

Derrick
 
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