# AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (VSS)



## PtownVdub (Jun 22, 2006)

I was doing some research and needed some clarification.
I am swapping an AWP 1.8T in my 1987 MK2 GTI. The 1.8T will be running with stock engine management with the immobilizer defeated. It is also running the stock O2O transmission as well as the stock MK2 instrument cluster with MFA. My question is whether or not the stock ECU needs to know the speed of the car? The speedometer is cable driven off of the transmission so the VSS signal wire that goes into the ECU is currently not connected into anything. Will this affect the way the engine performs? My understanding is that the only reason I would need to have the VSS signal going into the ECU would be the cruise control. 
Is my thinking correct or do I need to have a VSS signal going to the ECU? Thanks in advance for the help. http://****************.com/smile/emthup.gif


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## theguy1084 (Feb 4, 2007)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (PtownVdub)*

I think that you are correct from my understanding. I think the ecu also uses the speed signal for things such as ESP


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## PtownVdub (Jun 22, 2006)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (theguy1084)*

Cool ... thanks for the help. http://****************.com/smile/emthup.gif


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## bonesaw (Aug 8, 2004)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (PtownVdub)*

im guessing the mk4 ecu prob need to see speed like the ABA and VR swaps with the speed cuts. you can connect the the back of the MFA cluster to send speed signal to the ecu. i could be entirely wrong but i would think that if it needed speed signal in 93 they would need it now too. if the ecu has a connector for speed signal then it probably needs it. the cruise control is a seperate module.


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## jettaboy_gtx (Apr 12, 2003)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (bonesaw)*


_Quote, originally posted by *bonesaw* »_im guessing the mk4 ecu prob need to see speed like the ABA and VR swaps with the speed cuts. you can connect the the back of the MFA cluster to send speed signal to the ecu. i could be entirely wrong but i would think that if it needed speed signal in 93 they would need it now too. if the ecu has a connector for speed signal then it probably needs it. the cruise control is a seperate module.

theres no separate module for thecruise on MK4s its all done by the ECU.
Im not 100% sure but i think you are right, i think that speed signall is only used for cruise, abs, esp...and stuff like and you should be fine without it.


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## bonesaw (Aug 8, 2004)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (jettaboy_gtx)*

all you can do is run without it and see if you have a problem, if you do then connect it.


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## theguy1084 (Feb 4, 2007)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (jettaboy_gtx)*


_Quote, originally posted by *jettaboy_gtx* »_
theres no separate module for thecruise on MK4s its all done by the ECU.
Im not 100% sure but i think you are right, i think that speed signall is only used for cruise, abs, esp...and stuff like and you should be fine without it.

Agreed...there is no "cruise module" and what is ment by speed cuts


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## bonesaw (Aug 8, 2004)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (theguy1084)*

on ABA and VR if you rev too high or go to fast in 3rd 4th 5th gear it will cut fuel for 10 seconds.


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## PtownVdub (Jun 22, 2006)

*Re: AWP 20v 1.8T in a MK2 - Vehicle Speed Sensor (bonesaw)*

Well, I think I will leave the VSS signal wire going to the ECU disconnected for now. I will make sure that everything is wired up so that I can connect the speed signal that is coming off the back of the instrument cluster into the VSS signal wire going into the ECU.
Where do I pick up the speed signal off of the back of the instrument cluster? Thanks


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## obertheffect (Aug 16, 2021)

Hi guys, I have next issue, so I believe I can discuss it on this old topic 
Basically I have the same question as PtownVdub but I have a problem with that - I can't accelerate more than 150km/h for now, the ECU just cut my acceleration. I use stock firmware on my 1.8t AUM, and I just plugged speed cable, so my ECU doesn't receive speed signal from my gearbox. Can you help me with that? I want to use my Mk2 cluster and don't want to swap to any other dashboard. Or maybe this speed limit is not about VSS signal?


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## sdezego (Apr 23, 2004)

I can't tell you the answer whether or not the ECU needs a VSS signal or not, but if you have a Mk2 cluster *with MFA*, you can tap the VSS on the back of the cluster (center pin). Yes, the Mk2 Cluster that has MFA has a speed sensor which is a square wave hall just like the one on transmission. See my Cluster reference thread for more info. This was a G60, but 90 G60 is essentially same as Mk2 cluster with MFA. The unofficial Cluster Swap thread


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