Broken TPS ?

[Carfreak]

I adjust it so I see more than 90 deg on WOT.
Of course verify physically that the throttle valve is actually opening right.

Thnx!

[UrS4boy]

Out of interest what are the two switches?

http://forums.quattroworld.com/s4s6/msgs/20405.phtml

[twoqu]

I have seen that diagram. Thats why I was interested in this other switch.
I see an Idle switch, a potentiometer and it mentions that there is NO full load switch in the Motronic.
So was wondering where it was and what it does.

[prj]

I was too caught up in ECU terminology.
In the ECU, you have a WOT switch in the code, but yes, it does not actually come from the TPS, it calculates it...

There is no second switch inside the TPS, sorry for causing confusion.

[twoqu]

Thanks for the clarification!
I think you have been a little hard on the OP. He has stated that his Vagcom will not connect so he cannnot take advantage of the measuring blocks. I appreciate that Vagcom should be seen as an essential tool to diagnose problems.
If some of the info out there is basically incorrect, i.e the ohms measurements, it would be useful to know what the Motronic needs to see from the TPS to function correctly. Once we know that, we can as you have said, save others the cost of unnecessary replacements and their labour.

[prj]

Sorry, I don't see the logic in doing things backwards, because you don't have the tools to do it right.
If you don't have the tools or the knowhow to make them work, take it to a professional!

You don't torque head bolts with a wrench and a pipe on it. Why would you diagnose a sensor in any other way, than the one that is clearly laid out?
Same thing goes for MAF sensors. People measure resistance between contacts and what not, that's not the proper way to do things, especially if the ECU has all the facilities available to do diagnosis.

The reason there is so much conflicting information about the resistance, is because you are not supposed to do it this way.

It is interesting that for some reason on these cars people swap around parts etc without proper diagnosis when there are facilities to do so.
Perhaps because they are so cheap to maintain. I would have to sell my underwear if I used this approach on my RS4!

[UrS4boy]

If some of the info out there is basically incorrect, i.e the ohms measurements, it would be useful to know what the Motronic needs to see from the TPS to function correctly. Once we know that, we can as you have said, save others the cost of unnecessary replacements and their labour.

When/if new/better data is available, I will update my info post(s).

[twoqu]

I agree. But even if you have the right tools, you still need to know how to use them.
The reason that people use the resistances/voltages is because thats whats available from the Factory documentation which predate the widespread availability and affordability of diagnostic software.
If we know different, then here is an opportunity to clarify the issue, either here or in a new thread.

[prj]

Are you sure the factory documentation tells you to check resistances/voltages?
I would not be so sure.

[220bhp]

It is possible someone has misadjusted it, or the throttle cable is too long, or connected wrong.

I assume all this has been checked?

Also, this will have no effect whatsoever on ECU shutting down or not.
As for the resistance, it's dumb to measure ohms and whatever over the sensor, when you can see the value the ECU sees in VAG-COM.

Connect VAG-COM, open measuring blocks, push it to WOT, see if it's 90 degrees or above.
If it is, sensor is good, as that is the value the ECU sees. You can do this with the engine turned off.

Gotta love these mega threads about throttle position sensors. There's almost nothing they are used for in these ECU's, besides boost control and MAF-less limp mode.
Everything else is done off of the two switches.
Yet every month we have at least one TPS thread, where it's blamed on all kind of sorts of problems. Always ends up with it being replaced, and there being nada difference.

Out of all the cars I've mapped, I've never seen a single bad TPS. But I've seen loads of misadjusted cables.

I Appreciate what you say and value your comments, but may be you could go one step futher and tell us the correct way to adjust the throttle cable.I will say, I for one have had a problem with bad TPS causeing the turbo to glow red hot.
So I have learned to be aware of it.However please keep replying to all our threads, because we appreciate your knowlegable comments.But they would be even more appreciated if they where delivered,shall we say in a more sympathetic way.
Also not everyone has full blown vagcome,but then again may be we should.

[twoqu]

Well on the 3B there is no option!
Just checked the ABY Motronic Manual and they also list the resistance/voltages in addition to the correct way using diagnostic equipment!
So you can see how this stuff becomes the default way to test.

[mathias]

Sorry, I don't see the logic in doing things backwards, because you don't have the tools to do it right.
If you don't have the tools or the knowhow to make them work, take it to a professional!

You don't torque head bolts with a wrench and a pipe on it. Why would you diagnose a sensor in any other way, than the one that is clearly laid out?
Same thing goes for MAF sensors. People measure resistance between contacts and what not, that's not the proper way to do things, especially if the ECU has all the facilities available to do diagnosis.

The reason there is so much conflicting information about the resistance, is because you are not supposed to do it this way.

It is interesting that for some reason on these cars people swap around parts etc without proper diagnosis when there are facilities to do so.
Perhaps because they are so cheap to maintain. I would have to sell my underwear if I used this approach on my RS4!

I have been having trouble with My vagcom since day 1 not getting contact with the cable and so on, but thats What you get for 12 euros on ebay. Iam gonna take the car to a
Workshop but havent had the time for that. The car goes in limp mode on full throttle so Wanted to check the tps. Spent half à day Trying to get my vag com in order changed software. But i didnt managed to do that so all i had was à multimeter. And on that road it is. Offcourse i dont want to Spend money on things that might be wrong but What Can you when you dont get any fault codes and a week later the vagcom dont work

[mcandmar]

From memory you should see ~8 degrees throttle angle in vagcom when closed, make sure the throttle butterfly is clean as dirt build up will prevent it from closing properly. As mentioned above you can verify the idle switch in vagcom too. In my experience WOT will register anything from 97 - 101 degrees.

As for cable adjustment, pull the outer until the cable slack is taken up, then place the clip on the next slot out so the cable is slightly loose. Aint rocket science.

[twoqu]

Without pulling the fault codes, why have you identified the TPS at fault.
You don't need Vagcom to pull the codes, you can blink them out if absolutely necessary!

[prj]

Without pulling the fault codes, why have you identified the TPS at fault.
You don't need Vagcom to pull the codes, you can blink them out if absolutely necessary!

Exactly my point.

As for not getting VAG-COM to work - if the cable is not bad (which usually it is not unless you connect the black connector the wrong way around, then it's toast and you need a new one), then not getting it to work is usually user error.
There are plenty of guides online on how to get it to work.