VW Beetle Forum banner
1 - 20 of 34 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter · #1 · (Edited)
So, not on here that often and not sure anyone has covered this in any depth on here before - but thought I would impart some wisdom to my fellow buggers..?.. following on from my previous adventures :banghead:

http://newbeetle.org/forums/1-8-liter-turbo/113977-vcds-codes-rough-idle-misfires-turbo-boost-pressure-test-funky-smell-solved.html

I had cleared my previous ECU error codes and had one re-occurring fault code coming back on my VAG-COM / VCDS code 17579, causing all manor of issues:

* EPC light and Check Engine MIL
* Erratic idle speed
* Engine running badly at no-load
* Engine stalling for no apparent reason
* Several errors logged by the ECU

I came across a video on youtube (not my bug, but thanks to whomever posted it) with exactly the same idle symtpoms -

https://www.youtube.com/watch?v=qjUOLY86L-M&feature=g-upl

Anyway, a quick check on Ross Tech wiki revealed :

1 Fault Found:
17579 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal
P1171 - 35-10 - - Intermittent
Readiness: 0000 0001

Possible Symptoms:
* Malfunction Indicator Lamp (MIL) active

Possible Causes:
* Angle Sensors 1/2 for Throttle Actuator (G187/G188) faulty
* Power Supply for Angle Sensors 1/2 for Throttle Actuator (G187/G188) faulty
* Wiring/Connector(s) from/to Angle Sensors 1/2 for Throttle Actuator (G187/G188) faulty

Possible Solutions:

* Check Angle Sensors 1/2 for Throttle Actuator (G187/G188)
* See Measuring Value Blocks (MVB), usually MVB 062
* Power Supply for Angle Sensors 1/2 for Throttle Actuator (G187/G188) faulty
* Wiring/Connector(s) from/to Angle Sensors 1/2 for Throttle Actuator (G187/G188) faulty


So, after several hours of reading / swatting up on this particular code, it was evident that it could be a few things:

* Throttle body - needs a good clean, TBA / aligning or possible replace
* Wiring from ECU to pedal, or 6-wire wiring from ECU to TB
* Check / Clean Battery Grounding
* Possible ECU faulty
* Possible O2 sensor wiring - apparently they're powered by the section of the ECU that also connects to the pedal


I kinda knew the Throttle Body was ok, as a few months back I had taken it off for a 'proper cleaning' using Electrical Contact Cleaner aka. IPA / Isopropyl Alcohol. The two angle sensors are behind the black plastic cover that's held on with the clips shown. After very carefully removing these and the black plastic cover, the circuit board and variable resistor strips can be cleaned with IPA. You need to be very careful as the pick ups of the variable resistors are very fragile!

Auto part Machine


Now the "Throttle Actuator" is at the throttle itself - The angle sensors, or position sensors if you will, are built into the throttle body, along with the motor that drives the throttle body itself. These two variable resistors (angle sensors) connected to the throttle flap that feed the throttle position back into the ECU. They operate in tandem so the ECU can compare the two signals. If the signals don't correspond with each other the EPC (Electronic Power Control) light comes on and the ECU limits the engine revs. This is a fail safe system so that a faulty signal doesn't result in the throttle opening fully when it shouldn't.

As above from the Ross Tech wiki you can check the output status of the accelerator pedal position potentiometers / throttle angle sensors with VCDS - Measuring Block 062 - and verify that they change as you move the pedal.

If you don't have VCDS, you can also check the throttle body electrical connector for the correct voltage supply using a DMM / Multi-meter, as per pic below:

Text Font Line Diagram Parallel

The throttle body electrical connector wiring back to the ECU should also be within spec / ohm resistance range ~0.7-1.5 Ohms. After this, you can also check the wires for any shorts / continuity and resistance from Throttle Body -> ECU and ECU -> Throttle Paddle ...obviously all wires need to check out ok / have continuity with no shorts..

This throttle body electrical connector wiring can be prone to failing as it is at quite a hard turn very near the connector housing. With age, after many years with built up of heat, this can instigate the issue.

Some folk have replaced the Throttle Body and the same symptoms have re-appeared again after a couple of weeks..!

I believe the issue to be the 6-wire wiring loom between the Throttle Body and the ECU and those who have replaced this have had success.

But, as mine seemed to check out ok on the DMM - I just simply cleaned the connector and the throttle body side connector with IPA... and ...


well.. a few months on..

No more EPC and Check Engine MILs and NO MORE rough idle .. with No ECU errors logged either !

It seems to be running just fine without issue!

So, a lot of research.. albeit in the end a simple quick and easy fix!

I hope this helps others out there.. and I would urge those with the 1.8T just to spray / clean this connector.. and the Throttle Body if you can, first and foremost. :bigthumb:

btw. Put a new gasket on the Throttle Body (green paper-like in pic) if you remove it from your vehicle for cleaning.
 

·
Registered
Joined
·
15,839 Posts
So, in your case; do you think, it was the contacts inside the throttle body housing, that were dirty and cleaning them, fixed the problem? Or was the plug/connector; to the throttle body, that did the trick?
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #3 ·
Definitely the wiring-loom in my case - specifically the connector plug going into the Throttle Body. It has a very hard turn where it connects into the Throttle Body, and quite possibly with age the connector contacts just needs a good cleaning..

It worked in my case, as I'd already cleaned the Throttle Body some months back..

I'd recommend cleaning both connector-plug and the Throttle Body if possible, if you haven't already.. it's quite easy to remove the Throttle Body and give it a good clean anyway.
 

·
Registered
Joined
·
3,690 Posts
I am starting to see a lot of smaller female spring terminals that are getting loose after 8-10 years of high under hood temps and vibrations.

Find that I am starting to slightly pinch the female terminals closed when I have connectors apart for a better physical/mechanical/electrical contact.
 

·
Registered
Joined
·
15,839 Posts
v12bug, from your pictures; you actually removed the black cover, on the throttle body. I assumed you cleaned the terminals and contact areas on the circuit board; did you see any contamination on these brushes and carbon tracks?

Here is a video; discussing cleaning and diagnosing the throttle body: (in his case; one of the brushes was bent and was dirty):

https://www.youtube.com/watch?v=YcmA2Yc3JJw

Another video; discussing common failure issues with VW throttle bodies and VCDS measuring blocks, adaptation procedures:

https://www.youtube.com/watch?v=fdLA5pXUkk4
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #6 ·
Excellent find on those youtube vids Billy.. pretty much exactly the same steps / checks I carried out also..

yep, took off the Throttle Body electrical / black cover with those small metal clips.. using a small flat screwdriver. Although the clips are on there quite tight (be careful), considering it supposed to be a 'sealed' unit.. you still do get very minute fragments / specs of dirt etc..

So, I very carefully cleaned everything using a combo of cotton buds and soft electrical brush (or small soft toothbrush may do also) using IPA. The main 'throttle flap' area was cleaned with carb cleaner, as the guy mentioned in his vid.

In my experience, throttle bodies don't fail as such - they just need to be checked and cleaned properly and then installed with a TBA. VCDS is a must in these cases to determine correct performance.

..agree with jfoj.. these connectors with age seem to cause issues.. or in my case "16 Fault Codes" !!

Good idea to take these connectors off and do a visual inspection and give them a good cleaning, when you can.. quick & simple preventative measure.

Got to go outside now and fix the door lock on my Audi A6.. (pretty much the same lock on the Beetle) as the internal 'micro-switch' has become dirty. Again, these door locks are factory sealed units but are prone to getting very minute fragments / specs of dirt on the 'micro-switches' which can cause all manor locking/unlocking/alarm etc issues... VW / Audi would just have you order a new door lock.. which is $$$$$$!
 

·
Registered
Joined
·
15,839 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter · #8 ·
yes, thanks.. seen his video's before - good explanation on how to fix that particular issue..
all done now anyway :)
 

·
Registered
Joined
·
21 Posts
Thank you guys for your input. I printed off the thread and will take it to my mechanic so he can read it and follow your suggestions. I will also make sure he checks for vacuum leaks, booster leaks, etc. Thanks again and I will let you know the outcome.

rhondabug03
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #10 ·
well, well, well...

thought I'd finished with this..

but looks like the ol Throttle Body had other ideas.. and the issues have Resurrected!


Address 01: Engine Labels: None
Control Module Part Number: 06A 906 032 FT
Component and/or Version: 1.8l 5VT NB MT G 3996
Software Coding: 00001
Work Shop Code: WSC 00066
Additional Info: WVWZZZ9CZ2M604011 VWZ5Z0Z5141333
VCID: 75EBCB5E4FA118EEB2-5140
3 Faults Found:

17987 - Throttle Actuator (J338)
P1579 - 35-10 - Adaptation Not Started - Intermittent
17579 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal
P1171 - 35-00 -
17953 - Throttle Valve Controller
P1545 - 35-10 - Malfunction - Intermittent

Readiness: 0000 0001



Anyway, these new DTC's which appeared earlier in the year, I *hope* have now finally been put to bed .. and this update is more of an FYI for all, as I seem (hope) to have finally fixed this issue

As mentioned before the Throttle Body connector can become a bit loose or not connect properly over time and also due to the extreme temps under the hood .. thus causing some of the issues above..

So. I set about to purchase a new Throttle Body connector and at the same time check each of the 6x connector pins (can get easily damaged) and extend the wires from Throttle Body <-> ECU as they are very very tightly stretched when connected at the Throttle Body..

anyway, rambling over .. let the pics do the talking.. HTH :)

New Genuine Connector:

Product Technology Font Auto part Electronic device

Watch Watch phone Technology Electronic device Gadget

Electronic device


Re-wiring TB Connector:

Auto part Fuel line Engine Vehicle Car

Wire Fuel line Auto part Vehicle Car

Wire Electrical wiring Cable Technology Electronic device

Cable management Electrical wiring Wire Electrical supply Technology

Wire Auto part Cable Technology Car

Auto part Engine Vehicle Car Wire
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #11 · (Edited)
Once I had finished the wiring and connected it back up, I hooked up VCDS and tested the Throttle Body:

01-Engine => Group 062 => Fields 1 & 2

correspond to the output status of the accelerator pedal position potentiometers / throttle angle sensors - Verify that they change as you move the throttle is depressed or not (both fields should add up to 100%)

Definitely the best way to check the Throttle Body.. a couple of VCDS screen shots illustrating the above:

Text Blue Line Font Screenshot

Text Blue Line Font Screenshot

Looked good, so cleared the DTCs and completed a TBA (Throttle Body Alignment)

I went for a test drive, then after re-checked for any Engine DTCs. All good :cool:

Finished off the wiring with lots of Tesa Tape :thup:
 

·
Registered
Joined
·
15,839 Posts
Thanks for the update; this is the type of repair, replacement of terminal ends and throttle body plug/connecter, that i assumed would be needed, to fix this issue! I hope this finally; resolves your problems! :)
 

·
Registered
Joined
·
15,839 Posts
(fingers crossed); did you get your repair terminal ends and plug, from your vw dealer?
Thanks so much for taking the time; to document the problems, troubleshooting, repairs and resolution to these throttle body problems! Very few people; take the time to do this! We have been using this thread allot; to help others with throttle body trouble codes! Thanks again! :)
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #15 · (Edited)
no problem :)

just hope this helps others.. most of the time Throttle Body issues are quickly diagnosed by the 'technician' as saying... "erm, you need a new Throttle Body buddy!"

not true, imho.. better to follow some of these steps.. especially when a new VW Throttle Body costs serious amount of $$$$

I got the new Throttle Body connector plug from VW, cost just few bux..

then purchased a second hand connector with wiring from eBay - just for the wiring (again couple of bux) .. then used the best wires / connectors from both, to finalise the wiring on the new connector.. quite straight forward, pics of eBay connector below:

-I should add that one of the original connector pins on the throttle body connector was broken - hence probably why I was getting the above DTCs

HTH :)


Technology Electronic device Auto part Electrical connector

Technology Auto part Electronic device
 

·
Registered
Joined
·
2,545 Posts
good

Good write up and a way to finish things up. Hope this ends your throttle issues. thanks for sharing the pictures and info.
 

·
Registered
Joined
·
15,839 Posts
Just a FYI; for anyone that wants to fix this in the future. VW sells repair terminal end wires, that come with yellow insulation, to identify a repaired wiring harness and so, you could splice in, brand new terminal ends and have new wires that way. New plugs with pigtails; might be averrable online as well but I would trust the quality of genuine vw parts. I can only assume; aside from broken terminals, vibration and heat, will reduce the tension of terminals, which could cause intermittent connectivity problems.
 

·
Registered
Joined
·
25 Posts
Does the other end of this throttle body connector plug go all the way to the ECM? and does that make it easier to splice the individual wires rather than replacing the wires all the way to the ECM?
 

·
Registered
Joined
·
15,839 Posts
The signal comes from the ecm; so, i would assume so. The problems seem to be coming; from the heat/vibration, inside the engine compartment. So, it seems replacing the plug/terminal ends; fixes the problems but you could inspect the rest of the wiring or do wiggle/continuity tests (from throttle body plug to ecu plug/terminal), to confirm, look for any cracks in the insulation.
 

·
Registered
Joined
·
6 Posts
The signal comes from the ecm; so, i would assume so. The problems seem to be coming; from the heat/vibration, inside the engine compartment. So, it seems replacing the plug/terminal ends; fixes the problems but you could inspect the rest of the wiring or do wiggle/continuity tests (from throttle body plug to ecu plug/terminal), to confirm, look for any cracks in the insulation.
Guys I have this exact same problem same error codes 2013 golf mk7 I haven't done multimeter test on throttle body yet am not sure how to do it can anyone help with this so I can know if my wires are broken plus finding spares in South Africa is a nightmare. May I also add that my TB sensor codes started when my left LED tail light started to fail I am not sure if this does affect my wiring to TB I haven't changed the light yet still on order. I have cleaned TB also greased tomurbo arms, checked accelerator pedal all seems good I just need to do this continuity test on wires maybe replace my tail light and see

Sent from my BLA-L29 using Tapatalk
 
1 - 20 of 34 Posts
Top