Passat 3C Differential Pressure Sensor G450 is not responding

Hello,
I have been having a problem with the differential pressure sensor for several weeks, and unfortunately, I haven't been able to find any information about it. It started with the engine warning light. There was an error code stored for G450, and the reading was -30 at that time. I then tried resetting it with VCDS, but the value jumped to -40. After that, I ordered and installed a new sensor. The reading is now -40 again. What's noticeable is that the value is always the same. Whether the engine is on or off, whether I press the gas pedal, it's always -40. Resetting with VCDS no longer changes the value. Neither turning the ignition on/off has any effect. The value only changes when I disconnect the sensor's connector. So, the cable seems to be OK. It seems like the control unit is somehow malfunctioning and not responding anymore. I don't have any other ideas at the moment. Here are a few logs as well.

The negative sign is surprising. In my world, it would mean that he is measuring more pressure behind the DPF than before. Technically, it's quite difficult to achieve, as the pressure from the turbocharger would have to fall onto the DPF.

Ideas:
- Leak in the differential pressure sensor hose to "before DPF", blocked, whatever
- Hoses on the differential pressure sensor are reversed (but I think they have different diameters, so it should be difficult to do).

Inspection: Disconnect hoses from the sensor. Monitor value with VCDS.
Press on the "Vor-DPF" port. The sign should be positive.
Apply pressure to the "After DPF" port. The sign should be negative.
Warning: Do not overdo it when printing. A compressor may be too much. Max 300 mBar would be a good value.

Greetings
Guste

Hi,

Your "metrics" are -30, -40... what on earth is this nonsense. You can't be held responsible. But you can use KDataScope, as it also usually shows labels and units, besides VCDS not knowing this itself.

Everything about the differential pressure sensor:
/viewtopic.php?t=27732
/viewtopic.php?t=24160

The differential pressure sensor measures the pressure drop in the exhaust gases at the diesel particulate filter, and thus its ash loading and soot level.

Testing is easiest by blowing through, and of course, checking with a hose. Older versions also sometimes break down, but the current ones are quite durable.

Best regards, Rainer

After a long time, I tried again to find the solution... I think you can probably guess what problem exists based on the value itself. I still had the following values:

After many attempts, I thought about the wiring harness again. I had often felt along it with my fingers because you can't really see it alongside the engine. After measuring, one of the cables didn't register properly. After soldering in a new cable and turning the key on/off, the problem was gone. The VCDS function wasn't working due to the broken cable; the software crashed. Now that's working again too. So, a multimeter is the simplest and fastest way to find the fault...

Perhaps this will help someone.