B4 TDI ECU: Troubleshooting & Repair

Hello everyone, I'm new here and I already have a question.
I drive a B4 TDI, and after removing the engine control unit (ECU), the car won't start anymore. Does anyone have any idea if I might have damaged the ECU?

[email protected] wrote:

hello everyone, I'm new here and I already have a question. I drive a B4 TDI, and after removing the engine control unit (ECU), the car won't start anymore. Does anyone have an idea if I might have damaged the ECU???

Perhaps you should reinstall the control unit .

back to the topic...
Why was it expanded?
What has changed / been done?
Which engine?
...

The part is back in. It was taken out to see which part it is and whether the EEPROMs are soldered or plugged in. The motor is a 1Z with 182 Nm of torque and has 290,000 kilometers on it.
It simply has too little power compared to the 1Z engine from a 1995 Golf 3.
It reaches 185-190 km/h on the highway, but it takes a while. And the acceleration in 3rd gear, from 2000-4000 rpm, takes about 9-10 seconds.
What do you think, is it possible that I damaged this part ?

Well, if you've inserted the EEPROMs the wrong way around, that could certainly be the problem... It just depends on how wrong.

There are 8 possible ways to insert one of the EEPROMs, and the probability of inserting it incorrectly is 75%.

Hello Reiner, I haven't changed anything.
"The EEPROMs are soldered. I only removed the control unit, disassembled it (looked inside), reassembled it, and installed it. Could it be that there's a loose connection in the wiring harness, or is it the control unit itself? Oh, and one more question: the preheating indicator light hasn't been working (illuminating) for a while now (since the outside temperature has been above 5 degrees Celsius)."

[email protected] wrote:

hello reiner, I haven't changed anything. The EEPROMs are soldered. I only removed the control unit, disassembled it (looked inside), reassembled it, and installed it. Could it be that there's a loose connection in the wiring harness, or is it the control unit itself? Oh, and one more question: the preheating control lamp hasn't been working (illuminating) for a while now (since the outside temperature has been above 5 degrees Celsius)

.
Hello,

My name is Rainer, and I don't have a crystal ball to see if any of the pins on your engine control unit connector are bent or if any of the cables are loose.

You could just as well ask if you have athlete's foot. Without an examination of your feet, no one will be able to give you an answer.

Best regards, Rainer.

sorry, Rainer.

As far as I could tell, all the pins seem to be okay, and the motor is rotating smoothly. All the lights on the instrument cluster are working, but the engine won't start, as if the fuel cutoff valve has been disconnected. My question is, is it possible to damage the control unit by touching the circuit boards? I once ruined a 1Z control unit from a Golf 3 because I tried to desolder the EEPROMs myself. I didn't desolder one of the pins properly, and the circuit board detached and failed, but the car still started. It only ran in a limp mode, but it did run!

Quote:

My question is simply whether it is possible to damage the engine control unit (ECU) by touching the circuit board.

As long as the humidity in your apartment/workshop is within the normal range, and you're not sliding around on chairs with synthetic upholstery, damage from handling/ESD is very unlikely.

Perhaps some other connectors in the engine compartment were accidentally disconnected and simply forgotten?

I installed it outdoors, and I was there last Sunday, shortly after it had rained.
"I only removed the glove compartment and the cover under the interior fan, and I didn't touch anything in the engine compartment. In your career as a tuner and mechanic, have you ever encountered a situation where a component broke due to being removed, possibly due to improper handling when opening it or something like that?"
I just wanted to be sure and rule out any possibilities when troubleshooting, or to consider buying a new one directly. I'm worried that my local dealer won't accept a return if it's already been installed, since it costs around 800 euros.

Quote:

Has it ever happened in your tuning and modification career that an ECU (Engine Control Unit) was damaged due to removal, or possibly due to incorrect handling during opening

No. At most, something like "or so," but so far, it's always been fixable.

Why do you want to double the value of the car with a new ECU? Recycler...

Thank you for your answers.

That idea about using a recycling service is good, but as always, the problem is that we don't have the money for another one or a better one.

You should get a used control unit from a recycling center!

I've already called everyone in the area, and I haven't found anything.
but I found something online at a large auction house for only 70 euros.
I hope it arrives next week.

Hi everyone, another question for you. Has anyone here ever installed a different type of control unit? For example, replacing an 8A0907401B with an 8A0907401A?

It might work, but it's not guaranteed.
The vehicles may differ, for example, in their wiring or the type of WFS (Wireless Flight System).