[Biturbos4] Throttle Plate Test and Adaptation

Michael Benno mbenno at yahoo.com
Mon Nov 29 13:30:53 EST 2004


I pulled some relative information out of the Bentley manual on resetting, or adapting, the throttle plate (AKA: Throttle valve control module -J338-).

There are two methods; 1 Automatic and, 2 using Vag-com (or equivalent VAG tool).

1. Automatic Adaptation: First, disconnect the battery for a short interval (e.g. 10 min). This will register a learning requirement in the ECU for the throttle plate. Then "switch the ignition on for at least 6 seconds without operating the starter or depressing the accelerator." This will cause the ECU to perform the adaptation sequence, however, there is no way to know if the adaptation was successful here.

2. Using VAG com. This method will allow you to run the adaptation and verify if it was successful. Here is the process: Connect VagCom-com and select engine electronics control module (01), then select "Basic Setting" function (04), then Enter "060" into the display group number field and execute. The first two fields are the working ranges of the two sensors those values should be in the following ranges: Field 1: 3-20%; Field 2: 80-97%. The adaptation takes about 8 seconds and the timer is displayed in the third field. In the fourth field on the right you should see "ADP. OK" if the adaptation is successful, or "ADP. ERROR" if it failed.


Here are some more notes from the Bentley on this subject:

"The adaptation process enables the Engine Control Module (ECM) to learn the different positions of the throttle valve with the ignition switched on and the engine not running. These positions are stored in the control module. The feedback signal indicating the position of the throttle valve comes from the two angle sensors for throttle valve drive.

"If the Throttle Valve Control Module -J338- or the ECM is removed and installed or replaced, or if the voltage (power) supply to the ECM is interrupted, an adaptation must be performed."

"Note: The engine will not start during automatic adaptation"

"Note: If the adaptation process is interrupted by the control module, the cause could be one of the following: 
-The throttle valve is unable to close completely (e.g. because of dirt).
-The harness connectors (e.g.: at throttle valve control module) are loose, not properly connected or the contacts at the connector are corroded or bent.
-Battery voltage too low. 
-Throttle valve control module or wiring is faulty. 
-The engine was started or the accelerator pedal was depressed during the adaptation process. 
-Distortion of throttle valve housing (check bolts: 10 Nm)"

Lastly, IIRC, you are not supposed to move the throttle plate manually with your fingers because you can wreck the gears and motors. But I cannot find that statement in the manual. So I don't know where that info came form. When I cleaned my throttle plate, I did move it carefully, it still seems to work.

I hope this info is helpful. There is a bunch more trouble shooting info on the EPC system in the Bentley. Call me if you need help in the short term. I would recommend you get a manual if you don't have one yet.

Mike Benno
A6 2.7t 6spd 

Adam Jansen <aedan1 at hotmail.com> wrote:
Following advise I received I cleaned the Throttle Body and the seemed to 
help out, I only had one error on the way home (as opposed to mulitple...!)

I reset the DTC codes, but I dont know how to test the TB. Where would I 
find that info? I have a USB Vag-com, but the instructions are light.

I appreciate the help!


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