Hello.
I'm experiencing occasional, minor power issues with our 1998 ACV. VCDS lite has been displaying the error code 65535 - "Control unit defective" for some time.
When I look at MWB 10 field 2 (ambient pressure), I usually see a fixed value of 695 mBar. Occasionally, it jumps to plausible values just below 1000 mBar. And recently, the values have also increased significantly, reaching up to 1300.
I suspect that the pressure hose to the turbocharger pressure sensor has burst (I've experienced this before with a Golf 3 TDI). If I'm opening it up anyway to replace the pressure hose, I'd like to replace the atmospheric pressure sensor or at least resolder it.
Where on the circuit board can I find it?
Is the sensor available individually, or is there a suitable replacement part? Or is resoldering usually sufficient? Sometimes the sensor still provides plausible values.
Thank you very much, and best regards.
"On my first Galaxy TDI, I replaced the original sensor with a fixed-value one because I needed a quick solution. I set it to just under 1000 mbar and that was it. Since it never went into the mountains, that was the simplest solution. I never changed it back, because the engine control unit (ECU) was so difficult to remove."
Sommer: A4 B5 Avant 2,5 TDI Quattro Facelift (AKN silber)
Wartet auf H Kennzeichen: A4 B5 Avant 1.9 TDI Quattro (AFN Schwarz)
Hi.
Based on the images in the link, I identified the part, and based on the information that the problem disappeared after soldering measurement cables, I simply resoldered the connections.
Currently, I'm getting plausible readings again (969 mbar at home, down to 941 mbar during a trip to a higher altitude).
Besides replacing the expectedly defective pressure hose to the turbocharger pressure sensor, the car is now running smoothly again.
Thank you very much.
Greetings.