Throttle body diagnostic and repair guide for part number: 03L 128 063 B V110
This is actually an electronically controlled throttle body for several VW and Audi cars. I assume they are on other vehicle too but in some other shape. I would try to demonstrate as simple as I can how this unit is build up and how to diagnose.
Today I got this part in my mailbox for diagnosing and repairing from a nearby car repairer garage. Actually the car come up with several error codes and one of them was the “P2111 – Throttle Actuator Control System – Stuck Closed”.
My first question was “is this stuck or closed?” Then, never mind, I will see how this unit is build up and then I will know how this should work and than what is the behavior of this electronic controlled throttle body.
Actually, why I like to use this specific name “electronically controlled throttle body”?
Because it is an electronically controlled throttle body, it is not a simple one.
As I know, there are 3 types of throttle bodies:
- The old school type without electronic control module.
- Newer generation where the flap was mechanically controlled directly from the accelerator pedal but the car ECU got a flap position signal.
- The now days type where are all stuff electronically controlled, the accelerator pedal is no more connected to the throttle body.
The modern throttle body is controlled from the car ECU in a relation of the position of the accelerator pedal. So, in between the accelerator pedal and the throttle body is the vehicle ECU who commands the throttle body.
I put two red arrows between the ECU and the throttle body and one between the accelerator pedal and the ECU. The reason is because the communication between the throttle body and ECU is in two directions or two-way communication. Between the accelerator pedal and the ECU is one arrow pointing only to the ECU. This is because between them are one-way communication.
If you press the pedal to accelerate, or lift your foot from the pedal to slow down, the ECU recessives the resistance of the pedal and set up the flap in the desired position or so called “flap angle” but the ECU also recessives the actual position from the throttle body too.
So we have one direction communication from the accelerator pedal to the ECU and two-way communication between the ECU and the throttle body. The accelerator pedal is actually a big and robust potentiometer. And here is how the exactly throttle body with the control unit:
These are the main parts.
The most major problems why the throttle body is in a bad condition:
– Dirt in the throttle body and the flap can’t move freely.
– Brocken parts like a broken spring or failed / broken gear
– Bad control unit
– Bad electro motor
The spring is use to move back the flap to its initial point. If the accelerator pedal is pressed then the motor has to overcome the power of the spring and moves the flap in a desired position what is initialized by the ECU.
The magnet is actually in a relation with a hall sensor which is integrated into the black housing and no way to repair or to come close to it. It is used to tell the ECU where the flap is until operation condition.
The motor is used to move the flap to a desired position or angle what is requested by the ECU in relation to the position of the accelerator pedal.
The motor is actually a 12v DC brushless component. This motor has no minus or plus terminal because it can be moved in two direction, left and right, whatever is needed.
The big white gear:
The big white gear is connected to the flap and moves the flap when the motor is activated. There is also a black half gear under the white gear. This black half gear is used to move the magnet so the hall sensor can read the position of the flap and send it to the ECU.
The diagram part:
On the J623 you can see the T60/41 or T60/34 or T60/49 this means the 60pin connector where the wiring is exactly on the 41 or 34 or 49 pin on the ECU side.
So, if you disconnect the T60 connector from the ECU and the T5 connector from the throttle body you can check for continuity the wiring between the throttle body and the ECU.
Testing the signals from the ECU:
Check if reference voltage +5V are coming from the ECU with a voltmeter between pin 1 and 3 on the T5 connector.
Check with scope between pin 4 and 5 is there a signal of 12V or a PWM signal from the ECU for a short time ( around 5sec ) until somebody torn on the car but not crank.
Testing the hall sensor part:
Connect to pin 1 +5V and to pin 3 GND.
Connect a voltmeter positive lead to pin 2 and the negative lead to pin 3.
When the flap is open you should read a voltage around 4.5-5V.
If you move by finger the flap to a closing position, your reading should fall almost to 0V when the flap is reached the full closed position.
If you don’t have this kind of reading then you have a hall sensor problem.
I think this is not repairable because the whole electronic is integrated into the black cover of the control module. The only option to repair this kind of problem is to change the cover from a donor throttle body the exactly same type.
Testing the motor:
As this motor is a DC 12V brushless motor, and the terminals are directly connected to the ECU and have nothing to do with the hall sensor electronic in the throttle body electronic control module, I decided to directly power from my lab power source.
My setup on the lab power source was U=12v @ Imax=1.5A.
The flap should start to moving, but no noise or any other sounds come out and the flap also didn’t moved. So I decide to open the unit and inspect it from the inner side.
IF YOU DECIDE TO REMOVE THE BLACK COVER, PLEASE BE CAREFUL BECAUSE THE COVER IS FILLED WITH OIL!
Removed the motor and tried to reverse the polarity but also no current consumption was detectable on my lab power source and no motor movement too. Actually this motor is dead.
When I pushed the terminals on the motor in several directions until the motor was under power, sometime there was some sign of a starting condition but almost for a short time and low power.
Actually, I think the problem was a broken terminal inside the motor. I took out another motor from another throttle body whit the same characteristic and put it into this throttle body and fired up all that stuff and the flap was moving as it should move.
All reference reading from the hall sensor was in a reasonable limits and the throttle body was sent back to the garage. After a few hours I got a call from the garage does the car is repaired and the throttle body repairing was successful.
I hope you enjoy this tutorial and will save lot of repair time.
This article was prepared for you by Christian Robert Adzic from Novi Knezevac-Serbia.
Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
P.S- If you enjoyed reading this, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!
Note: You can check his previous post in the below link: