LMM OK, but error message?

Hello, maybe you can help me!

I have a 1.9L (90 horsepower) TDI Octavia, manufactured in 1997, with 110,000 kilometers on the odometer.
The car has been running perfectly fine with a chip tuning for a very long time.
Now, he's experiencing a loss of power, and the error memory indicates a problem with the mass airflow sensor (MAF).
'Short circuit detected after +. The mass airflow sensor (MAF) was replaced free of charge (it was only one year old), but that didn't fix the problem. Then, a guaranteed working MAF sensor from another vehicle was tried, also without success. Does anyone have any ideas?'
Best regards, Stefan[/b]

Hello,

These error messages are usually caused by damaged wires or cables.
Have you checked the pipes, or has someone else checked them?

Was that the work of a specialized VAG workshop again?

Hello,
Of course, it was a breach of contract.
The response to my question about the cables was that they had, of course, been checked, and furthermore, a different error message should appear (short circuit after -).
Since this topic is new to me, I would like to know if I can measure the voltage at the disconnected connector, where the control unit is located, and what other methods are available to check the connections and cables.
Best regards, Stefan.

The answer to my question about the cables was that they had, of course, been checked, and furthermore, a different error message would appear (short circuit after -).


aaah yes

Well... exposed wires can sometimes cause a short circuit with each other.

The LMM is supplied with +12V and +5V for power and as a reference voltage.
If they are short-circuited to ground, you will get exactly that error message.

I'd like to focus on the cable entries and also check the engine control unit connector.

The following values should be measurable at the connector of the mass airflow sensor:
pin 2 = 12V
Pin 3 = Ground.
Pin 4 = 5V.
Pin 5 = approximately 0V (absolutely no more than 5V).

Pin 5 is connected to the output of the mass airflow sensor (MAF). When the MAF is connected, you should see 1V on this pin (with no airflow).

CU Gremlin.