AGR Potentiometer Check: BLS with DPF.

Hello,

Caddy 2KA, 1.9 TDI, BLS engine, original DPF, 105 hp (0603/AGB).

How can the potentiometer of the EGR valve be tested? This refers to the EGR valve shown in the picture.

Normally, you can test a potentiometer by connecting the middle terminal to one of the outer terminals using a multimeter and checking for a certain resistance value. This works for me as well. However, when I push the potentiometer inwards, the resistance doesn't change.
When it comes to cars, many things are different compared to regular electronics, which can sometimes seem illogical if you're used to how things work in other areas.

Perhaps someone has an EGR valve that they could use for testing. Or, does anyone know how to properly measure this component?


To describe the plug connection of the plastic cover on the EGR valve, as shown in the first picture:

The two top contacts connect directly to motor terminal A and terminal B, respectively, without any resistance. The three bottom contacts are connected to the potentiometer.

Since it doesn't necessarily have to be a potentiometer, for example, inductive measurement is used in BRE motors.

The plastic gears in the actuator are more likely to break, so it's best to disassemble it and take a look.

I just took it apart and put it back together, and now I'm a little smarter than before , and luckily, I didn't break anything.

Unfortunately, I only took one picture, which shows what's inside.
This core is pushed out by two feathers.
Above that, visible from the outside, is another cover, underneath which sits a small piece of electronics that has been encased in this waterproof gel. (Unfortunately, I didn't take a photo.)
If you open the lid first, you might suspect that there's a potentiometer underneath... However, it's likely that the resistance is being measured inductively, as the core is equipped with metal and surrounded by an invisible coil.
I had to re-glue the lid because it wasn't staying on anymore.

A potentiometer is something else; that's an inductive rotary angle sensor.

I got this information from a potentiometer supplier in an automotive workshop. It seems that was incorrect information.

Hmm, that's linear motion.

Quote:

How can the potentiometer of the EGR valve be checked? It refers to this EGR valve, as shown in the picture.

The best tool for this is the STG (control unit) -> Connect it -> Turn on the ignition -> Go to the corresponding measurement block, move the sensor, and check the values for plausibility.
Only when something appears to be defective should one consider how to test the "component" before potentially confirming that it is indeed defective.