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kingtaco94

Throttle plate stays closed will not idle

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kingtaco94

Hey everyone, 

 

Another issue with my 96 6n. Now the throttle plate doesn't seem to open when i start the engine.

 

At first i noticed the plate would open just enough to allow the engine to start/idle and there was a loud buzzing noise coming from the throttle body (disappeared when i unplugged it). Then the plate started rapidly flicking between the closed and slightly open position. And now the plate doesn't open at all while the engine is cranking, making it impossible to start the engine and leave it to idle. 

 

I can start the engine by putting the accelerator pedal down so i know it's an issue with the throttle body itself. I Have already replaced it for a new throttle body and have the same issue. Am i right in assuming it's a wiring fault of some kind, Bad ground, open circuit?

 

Thanks in advance,

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nige8021

When you replaced the throttle body, did you do the alignment test with VCDS ? if not the ECU doesn't know the butterfly position so it will struggle

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kingtaco94
38 minutes ago, nige8021 said:

When you replaced the throttle body, did you do the alignment test with VCDS ? if not the ECU doesn't know the butterfly position so it will struggle

Nope, I don't Have a vcds nor do i know anyone with one, so i'l likely have to get a mechanic in for that. Be ideal if the problem's that simple

 

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kingtaco94
59 minutes ago, nige8021 said:

When you replaced the throttle body, did you do the alignment test with VCDS ? if not the ECU doesn't know the butterfly position so it will struggle

actually i just had a quick look on the internet machine, is this something i could do with a cheap cable off amazon and the vcds lite package from ross tech? 

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nige8021

I think you can do the throttle body alignment with the "Lite" version but I'm not 100% sure, as I have the full system so not sure what limitations there are on the "Lite" if you search for Gendon they are the UK dealers for Ross-Tech they should be able to confirm if it will work.

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kingtaco94

Yeah i gave Ross tech a ring and the guy on the phone said i should be able to do the throttle body alignment with the lite version, so i've bought a cheapo cable and will hopefully be able to have a crack at it tomorrow, Cheers for the suggestion nige

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davidw123

great info and link, would like to know if this sorts the problem kingtaco94 , I just like to know this kind of stuff as we'll never know it all but it can make life easier.

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kingtaco94

I'm getting nowhere with the cheap cable and VCDS lite. I set the cable up properly so far as i can tell with the appropriate drivers and the cable is communicating with VCDS. However i can't connect to any of the control modules on the car. The only one i've had any success connecting to was the "03-ABS Brakes" module

 

i performed the OBD-II compatability test and it returned saying my car is not OBD-II compatible. Does this mean my car is not compatible with VCDS? 

 

from what i can tell it could be a few things. 

 

1. the cheap cable is just rubbish

2. I just haven't set the cable up properly to function with VCDS

3. My car is not compatible with VCDS and maybe needs a different/older software package

4. My ecu's gone

 

By the way nige8021 i spoke to a guy at ross-tech on the phone and he said you can do the throttle body alignment with VCDS lite, so i'm still holding out hope haha 

 

Any advice or help for me?

 

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nige8021

Your car won't be OBD-ll compliant, as that only applies to post 2001 petrol or 2005 oil burners, but your car will talk to VCDS but rather than giving the OBD-ll "P" fault codes it will give 5 number codes.

 

When you initially select VCDS go to the "Program Options" from that you can test the interface lead and make sure you click the "Save" button after it says interface found, then you can either select the "Auto Scan" and scroll down the Chassis Type till you get to 6N Polo select that, then click the "Start" button and with the ignition in the ON position it should then search for all the connected computers and as it reaches one, it will check for any stored codes, once it's finished you can save them, then click the "Clear DTC's" and then re-run the scan to make sure they have been deleted. When that is all OK go back to the start screen and click the " Select Control Module" and then click the " 01 Engine" and follow the instructions from that link I posted before

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kingtaco94

Thanks for the quick response nige, i have done all of that as far as "clear DTC's" step. I will give that a go tomorrow. 

 

you see so far every time i have tried to select control module "01-engine" VCDS just arses about for about 10-15 seconds before giving a "no controller response" message. 

 

I have also read on another thread that my modem could be operating on one of the COM ports and that VCDS will try and communicate with my laptop's modem in stead of the car's ECU. So i'l try deactivating the modem and having another go tomorrow as well.

 

Just a heads up i'm using VCDS on Windows 10, just encase that's relevant

 

Will report back if i make any progress or need any more help cheers.

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nige8021

The operating system shouldn't make any difference, however both of my diagnostic laptops are old Panasonic toughbooks running winXp

 

As yours is an early 6N1 all the diagnostic lines go to a commoning  tag block on the fusebox, so if your ABS was responding ? it might pay to have a look at this tag block and make sure all the wires are clean and connected.

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kingtaco94

It turns out it was an issue with my USB ports for some reason. I've tried another one and managed to communicate with the engine. I've paid for the full version of VCDS lite and i should be able to use it by Tuesday hopefully so i'l report back then, cheers for the help so far Nige.

Edited by kingtaco94

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kingtaco94

Just got the full package for VCDS Lite, so i decided to hook it up and do an autoscan before attempting the throttle body aligment and i got back the following reading

 

Address 01: Engine Labels: 032-906-030-AEE.LBL

Controller: 032 906 030 D

Component: MARELLI 1AV 1984

VCID: 0B69B4E42A5D

1 Fault Found:

00516 - Closed Throttle (Idle) Position Switch (F60)

27-00 - Implausible Signal

Readiness: N/A

 

 

Any ideas? my first suspicion is an open circuit on the three pin connector going into the throttle body or maybe a bad ground?

 

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nige8021

Have a look in this

I've posted the pin connections for the throttle body so you can test the throttle closed switch

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kingtaco94

Hi nige, i just got the measured the voltage for the pins in the throttle plug, here are the following readings

 

pin 1 – black wire – 5.9v

pin 2 – red stripe / white – 6.0v

pin 3 – grey / yellow – 10.91v

pin 4 – red / white stripe – 5.6v

pin 5 – red / grey stripe – 1.9v

pin 6 – not there

pin 7 – brown / green stripe – 0.0v

pin 8 – white / blue stripe – 1.85

 

So pin 3 is the throttle closed switch yeah? is it not supposed to have a reading that high? do the rest of the pins look ok? 

Edited by kingtaco94

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nige8021

This is from Autodata for pin 3 of the throttle body

 

E1BB46F5-CFA6-4D47-9848-9898FC26D3AB_zps

 

So with the connector on the throttle body you should have 0v when the butterfly is closed and 9v+ when it's off the closed position.

 

Pin 5 when the throttle is closed you should have around 4v and dropping down to 0.8v when fully open

 

8BC589AF-202E-49C5-AF25-D6C29A626042_zps

 

The rest of the voltages look OK

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kingtaco94

ok

pin 3 - throttle closed = 0.02v

pin 3 - throttle slightly open = 10.9v

 

when i opened the butterfly ever so slightly off of the the closed the position the voltage immediately shot up to 10.9 and stayed there until the throttle butterfly was wide open.

 

pin 5 throttle closed = 4.3v

pin 5 throttle wide open = 0.8v 

 

so it looks like pin 5 is ok.

sorry nige but i'm a complete noob at this stuff. what could be the issue here with pin 3?

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kingtaco94

I forgot to mention, but when i took those readings earlier, the throttle plate was fine, Stayed still the entire time and made a low level buzzing noise.

 

I just had another look and tried to take some voltage readings again and this time when i turned the key the throttle plate started rapidly vibrating again. ever so slightly fluctuating between slightly open and shut i think. I decided to have a look through VCDS again and returned the following codes:

 

4 Faults Found:

00518 - Throttle Position Sensor (G69)

30-10 - Open or Short to Plus - Intermittent

00530 - Throttle Position Sensor (G88)

30-10 - Open or Short to Plus - Intermittent

00516 - Closed Throttle (Idle) Position Switch (F60)

27-00 - Implausible Signal

00282 - Throttle Position Actuator (V60)

36-10 - Open Circuit - Intermittent

 

shall i just call the auto electrician and be done with it? i don't seem to be making much progress with it myself

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nige8021

Those codes might of been set by you taking the voltage readings.

 

Was it a brand new throttle body or a used one? It looks like the throttle closed switch is working OK as it went from 0v to 10.9v as soon as you moved it off the closed position and stayed there

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kingtaco94
1 minute ago, nige8021 said:

Those codes might of been set by you taking the voltage readings.

 

Was it a brand new throttle body or a used one? It looks like the throttle closed switch is working OK as it went from 0v to 10.9v as soon as you moved it off the closed position and stayed there

ah ok then, that would make sense since they were intermittent. Yeah it's a brand new throttle body. The new one so far has mimicked the same symptoms/problems as the old one

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nige8021

Have you managed to do the alignment procedure yet ?

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kingtaco94

no vcds wouldn't allow it. for some reason i could not clear all dtc's. Then when i went to throttle control basic settings the top right dipslay doesn't say ADP run or ADP OK it says "3" i think. i'l go run the vag com in a minute to get a screenshot of the basic settings i get for you

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kingtaco94

here, hooked the up VCDS, for some reason the butterfly had stopped fluctuating and has settled again. but still can not run the Throttle Body aligment. And i met all the test conditions before checking basic setting 098, coolant temoerature, clear all dtc's ect.

Measuring block 098.jpg

Measuring block 003.png

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nige8021

If you can't get the adaption to run, sometimes you can get the ECU to learn the throttle positions by going for a 30 min drive and with varying loads on the throttle including a few, flat to the floor with the pedal

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