Brake Not Releasing When Clutch Engaged?

I'm new here, so let me start with a brief greeting:
GREETINGS TO EVERYONE!!!

I have a Golf with a 110 horsepower TDI engine, manufactured in January 1999. Unfortunately, I don't have the MKB (engine code) number.
The clutch is not disengaging even though the driver is pressing the clutch pedal; it only works with the brake pedal. The switch attached to the clutch pedal has already been replaced, but that didn't solve the problem.

The error memory shows two errors.
(This probably has nothing to do with it) - The servo motor for some kind of valve is defective (it seems to be related to the air conditioning system).
2) CAN - faulty or missing signal from the transmission control unit.
(Does he have anything to do with it?)

I have always believed that only automatic transmissions have a transmission control unit, but mine has a manual transmission.

Does my little cucumber have a transmission control unit?
if so,
Can the transmission control unit be the cause of my error?
if so
What should be done?

otherwise???

marki

"In my opinion, manual transmissions don't have a control unit. Please check your clutch switch (it's located at the top of the pedal; you can adjust it by pulling out the plastic knob and pressing the pedal down)."

Greetings, Rainer.

Hello,

If the error relates to the transmission control unit and you have a manual transmission, your engine control unit is incorrectly coded. This also explains why your clutch switch isn't disabling the GRA (Gearbox Ratio Adaptation): An automatic transmission doesn't have a clutch, so it's not accounted for in your coding.

Please share your main key board (MKB) and general key board (GKB) configurations. I will then provide you with the correct encoding.

I will check the switch and post about the MKB as soon as I find it - where are they located?

Incorrect encoding? Could it have changed on its own? Everything was fine before.
Also, the other gray functions are working – is this a contradiction, or does it fit with your assumption?
marki

Forget that sentence, Michael - of course it fits!

Please provide the German text you would like me to translate into English. I will then give you only the translation, without any explanations.
Also, the other gray functions are working – is this a contradiction, or does it fit with your assumption?
marki[/quote]
Please provide the German text you would like me to translate into English. I will then give you only the translation, without any explanations.

marki

Hello,

You can find the MKB and GKB codes in the service booklet at the beginning.

Okay, the engine code should be AHF.
Gearbox identification letters: DEA.

I just checked the switch on the clutch pedal.
Adjusting the knob didn't do anything.
... expanded and measured to see if anything happens when it's activated.
In its pressed state, it shows 0; when released, it shows 1.
Not being a huge electronics enthusiast, I had the device set to measure ohms, and now I assume that the result indicates whether the circuit is open or closed.
The device seems to be working properly, but there's still the issue of encoding the engine control unit.
I'm just surprised that the error suddenly appears without anyone having worked on the control unit.

Hi!

When the GRA (Gas Return Assist) is active and the powertrain is unloaded, it's possible to shift into neutral without using the clutch. The system detects the neutral position by recognizing a fluctuation in engine speed without a corresponding change in vehicle speed, and immediately deactivates the control. When the clutch pedal is pressed, the shift interlock is first activated. This disables the GRA. If the clutch is fully disengaged, the GRA would be deactivated at this point, even if the switch is faulty, due to the sudden jump in engine speed. Therefore, if your engine revs up when you press the clutch and the GRA tries to regulate, it's definitely not a problem with the switch, but rather with the control unit, as Michael already mentioned.

Best regards,
Uwe

Hello,

Your control unit should be coded with the value 00002.
To code the engine control unit (ECU), you need a diagnostic tool.

- Select "Engine Control Unit".
- Function coding.
- Enter the new code: 00002.
- Save
- Exit control unit.
- Turn off the ignition.
- After approximately 2 seconds of ignition, turn the ignition on again.
- Verify encoding.

hi hi
First of all, a heartfelt thank you to all of you for your kind help.
Things are really fast here.

The engine control unit already starts limiting performance when the engine speed increases.
However, there's no immediate response; it takes approximately 1-2 seconds.
Depending on the speed (and consequently, the engine's operating state), the indicator is already showing values between 4,000 and 5,000. This can be somewhat distracting while driving.

I'm going to find someone with a diagnostic tool and check the settings.

Thanks again - I'll be in touch.
marki

Hello,

If you have connected the diagnostic device, you can also immediately check the function of the clutch switch.
Specifically, in measurement block 6.
The bit mask in display field 3 indicates the status of the clutch switch, brake switch, and the GRA lever switch.
When the clutch is depressed (I can only speak about the AHF here, but perhaps the bit is different for you, although the behavior should be identical), the 6th bit from the right should change from 0 to 1.
Okay, for example, changing "000 011" to "100 011".

Best regards, Rainer.

I will do so.
I might need to double-check something there.

I think I might also be a candidate for a new LLM.
The descriptions I read in the forum seem to fit my car quite well. It reaches 180 km/h with a tailwind, has uneven acceleration, and when it revs up, it sometimes pulls better and sometimes worse, and then two seconds later, the tachometer starts moving faster again – that's probably what they mean when they talk about 'wave-like' acceleration.

Should I have anything else checked on the diagnostic device regarding this problem? Although no error code was indicated, should I pay attention to any entries in the measurement data blocks?
marki

P.S. Have a nice rest of the weekend.

Hello,

Please print out the measurement data blocks and then post them here.
Then you might be able to see further.

If I'm lucky, I might get access to a diagnostic device today.
The owner has distanced himself from supporting me in my endeavor.
I plan to make it myself.
Just in case...
What actually happens if the code is incorrect?
Can I simply enter the old value again and everything will be back to how it was before, or have I changed something that I won't be able to easily undo?

Hello,

"Completely incorrect codes will not be accepted. However, you can always enter the old code again afterwards..."