Need a new throttle body?

[geoff_gti]

Cheers guys. Mine has been cleaned/serviced once already and the intermittent idle fault has started coming back occassionally. (You know the deal, idles up & down between 1200 and 1400rpm or so, air con seems to cut out, and cruise control disables itself lol)

Can they be serviced a few times or will it need to be replaced soon? The car went into 'safe mode' once too which I'm pretty sure was related, just lost acceleration power as though it wasn't boosting. Was fine again next time I drove and hasn't happened since.

Oh and the gearbox has decided to start banging intermittent when I select 1st if I'm not completely stationery....but that's another topic. No I haven't been thrashing it!!

[Madz]

Yep, sounds like what mine's doing - it only runs 5psi boost in safe mode too which just isn't enough Also on hot days in syd traffic (coming back from the wrecker) it's clearly not an option to have no A/C below 2000rpm

If it's just a carbon build up causing it to play up, this can be cleaned as often as need be - pretty simple job and seems to commonly solve the problem. From what I've been able to work out though there are no servicable components inside them so if something fails internally you are up for a new one.

That said I've currently got mine open having a sniff around inside it for anything obviously wrong. If I can figure out how I'll post up some pics. It's quite elaborate in there, but definately not $1000+ elaborate!!

[Madz]

Some Pics

If anyone is interested, here are some pics of the TB with black cover removed so you can see some of the internals:

[h100vw]

Mick, we are looking at 2.9K between pins 1 and 2.

Gavin

[gpk_gti]

what happened with this story?????

[Madz]

I'm back at work now and have had heaps on outside of work so haven't had a chance to look at it the last week. I've got a mate trying to source a throttle body in Europe as they are too expensive here. Gavin's been giving me some ideas and I'm still hopeful of maybe being able to get to the bottom of what's wrong with mine, but I need the car running so can't take too many risks with it until I can secure a replacement. I'll post up a few more details of the tests I've done in the next day or so.

[Madz]

Here's some more details on the tests I did on the two units I've got. Not sure how interested people are going to be in this, but it might be useful to someone one day.

Note that the pin numbers here do NOT match the numbers physically visible on the throttle body - for whatever reason the wiring diagrams are numbered differently. The pin numbering I used matches the wiring diagram and is as follows:

1 3 5 7 
2 4   8

The missing pin is Pin 6.

Pin Functions
1. actuator +12V
2. actuator GND (idle control + cruise) - (switched ground for actuator control)
3. throttle closed = pin 7 / open = ∞ - only detects cable/manual operating of throttle
4. +5V
5. Throttle position sensor - measures position of throttle valve
6. Not connected
7. GND
8. Actuator position sensor - measures position/angle of electronic actuator - not moved by throttle cable

Wiring Diagram Snippit


Pin Measurements

Test Unit 1 is the non-cruise unit 06A 133 063 G (Audi A3)
Test Unit 2 is my suspect cruise control unit 06A 133 063 F

Check throttle open/closed switch:
Measuring with a multimeter resistance between pins 3 and 7.
Test Unit 1: At idle: 0.6Ω. As soon as I moved the throttle: open circuit
Test Unit 2: At idle: 0.6Ω. As soon as I moved the throttle: open circuit

Check throttle position sensors:
Total resistance: Between 7 and 4 (doesn't vary with throttle position)
Test Unit1: 0.95kΩ
Test Unit2: 0.95kΩ

Check throttle valve potentiometer:
Between 5 and 4:
Test Unit 1: At idle: 0.71 kΩ increased to 1.45 at 3/4 throttle back to 1.40 at full throttle.
Test Unit 2: At Idle: 0.76 kΩ increased to 1.51 at 3/4 throttle back to 1.43 at full throttle.

Check throttle valve positioner potentiometer:
Between 8 and 4:
Test Unit 1: At idle: 0.69 kΩ
Test Unit 2: At Idle: 0.65 kΩ
These readings don't change as I manually move the throttle, they will only change as the throttle is electronically operated (this sensor measures the movement of the electronic component of the throttle).

Check Throttle Actuator:
Between 1 and 2:
Test Unit 1: 2.9kΩ
Test Unit 2: 23Ω

This last test showed the most significant difference between the two units - Gavin has also measured his unit and found it to have 2.9kΩ as well, but it is also a non-cruise control unit so I'm still not sure whether this is the result of a different rated actuator in the cruise control unit or a sign of the underlying problems with mine. Would greatly appreciate it if someone with a cruise control unit would be able to measure theirs.


Internal Wiring/Connections

As far as the internal connections go (this is the internal wiring under the black cover, not the external wiring harness):

1 3 5 7 
2 4   8

The missing pin is Pin 6.

1-black (to actuator)
2-white (to actuator)
3-blue (to inner side of throttle open switch)
4-red
5-green
6-n/c
7-brown and also connected to outer blue wire
8-yellow

[dubster99]

Was this ever fixed? Im having the same problem!

[Madz]

Hey mate no unfortunately i needed the car back on the road and didnt have time to fiddle with it, so gave up on it and got a mate who was in the czech republic at the time to source me a new skoda one there which was quite a bit cheaper (but still not cheap)! I'm not sure if i still have my old one lying around, will have a look might be a good guinea pig for you if you're going to have a crack at repairing it....

[dubster99]

So the new throttle body fixed it though?

[schwartza3]

Just read the entire thread, bit surprised no one suggested disconnecting the -ve terminal for 5 minutes again, connect back up, turn ignition on without turning the car, leave for about 2-3min from memory, the throttle body self aligns, you'll hear it ticking over, done this plenty of times on mine

[dubster99]

Ive read about that but never tried it. Alot of people saying they needed vagcom for it to allign it properly as it was the 'only' way. Will try it today and see though before buying a throttle body

[Madz]

I had vagcom at the time. Pretty certain I tried all that. Hopefully it will work for you, but for me it was definitely some sort of fault with the throttle body itself. The new one solved the issue immediately

[dubster99]

So ive tried a second hand throttle body and same codes came up and would not clear! Surely both arent faulty? same problems as before, erratic idle, stutters when trying to drive it. No clue whats going on now!

[Madz]

Have you got vagcom? For me the old throttle body wouldn't align using that, where the new one did no problems. Would be interested to know if the second hand one aligns or not....

I can't remember too much about the whole thing sorry and don't have the car anymore, hopefully one of the other guys will be able to help more