Magic Spell Blocked: A4 Document Analysis (12/99)

Hello, I'm having the following problem!
Recently, my A4 has been making absolutely no noise anymore .
When I turn on the ignition, only a few indicator lights come on, and the preheating indicator doesn't light up at all – not even for a second.
"Error memory indicates: Combination instrument error. Engine control unit locked!"
All other control units can be read without any problems using the automatic scan function.
"However, when I try to access the immobilizer control unit, the tester says that access is not possible ."
The engine won't start; it's definitely cranking, but the WFS (water flow sensor) is shutting off!
I hope for your help.

I would start by checking the fuse for the combination instrument.

Best regards, Rainer.

Hello!
Has a long-standing issue been identified as a mandatory error?
Has this happened before?

How do you access the WFS control unit?
The control unit is located in the instrument cluster.
Do you have the large display in your AI unit? If not, you probably have a Jaeger AI installed, and those are known to fail frequently.

It's not even worth repairing because the new price is around 230 euros.

Sure, here's the translation:

"So, news ticker!"
Today, the car door opened, and the speedometer lights, clock, date, and mileage display turned on. When I turn the ignition on, it glows briefly but then turns off. It won't start.
"WFS OK, no blinking lights, no error codes!"
"Engine control unit (ECU) is okay, no flashing lights, no error codes!"
magic, curse, what could it be?

Up to the Mj98 A4, the WFS (Window Defogging System) was located in an external control unit. This is situated behind the ventilation/air conditioning controls. And it doesn't require the KI (Key Interface) to start up; I tested this on my old car when I retrofitted the onboard computer.

If the engine control unit (ECU) isn't responding, check the relay that supplies power to it. It's located in the front of the engine compartment, in the same box as the ECU, and is labeled with the number 109 or 219. This relay often fails.

The preheating indicator light is powered directly by the engine control unit (ECU). If it doesn't illuminate at all, then it's not receiving power.

bastion wrote:

Up to Mj98, the A4 had a WFS (Window Film System) in an external control unit. This is located behind the ventilation/air conditioning controls. And they don't need a KI (Key Interface) to start; I tested this on my old one when I retrofitted the onboard computer. If the engine control unit (ECU) isn't responding, check the relay that supplies power to it. It's located in the front of the engine compartment, in the same box as the ECU, and is labeled with the number 109 or 219. This relay often fails. The lamp for the preheating indicator is powered directly by the engine control unit (ECU). If it doesn't light up at all, then that component isn't receiving power

.

I have a facelifted 12-99 AFN model! WFS is displayed on the instrument cluster!
"The engine control unit is receiving power, otherwise it wouldn't be able to read any error codes. This has been the case since the fault first appeared." "It's also pre-glowing again as of today, which is very mysterious. It just won't start properly!"