Tachometer G28: Troubleshooting and Diagnosis

Hello to all TDI enthusiasts out there.
'The following problem occurred with my Audi 80 1.9 TDI (1Z engine):'
Sudden power loss, jerking, initially only during high-speed highway driving, but soon afterwards in every speed and load range. Nothing unusual could be observed only when idling.
Reading the error memory revealed error code 0513: implausible signal from crankshaft speed sensor G28.
Okay, here's my question to the community: Is there a way to determine if the problem lies with the sensor itself (i.e., a defect), or with the trigger ring or the wiring?
Okay, I've checked the connector to the control unit, and it seems to be fine. So, it shouldn't be broken or damaged.
Am I correct in assuming that the G28 must have a defined internal resistance, perhaps somewhere in the 100-ohm range?
'Because in mine, the resistance goes to infinity, which means the connection is broken.'

I would be very grateful for any answer.

Best regards, Flo221281.

Hi.

According to the service manual, the target resistance value for resistor G28 is 1 to 1.5 kOhms.

If you want to measure the magnetic properties (an LCR meter or similar device is required): the component in my tractor has an inductance of 1.3 H.

Deleted upon request.

Hello,

I found the defect: a wire in the cable (coming from the G28) was broken right at the connector. I replaced the sensor -> it's working perfectly again.

I find it quite weak of Audi that a part like this would break; it's not a wear-and-tear item! But with this kind of defect, that impression could easily be created (because the cable was almost completely worn through at all its attachment points).

And thank you again for the tips.

Best regards, Flo.