Replaced the coolant temp sensor. fixed short GP cycle, now temp gauge is wrong.

I had a short Glow plug cycle issue. I unplugged the coolant temp sensor plug and it was the long cycle. So, I assumed CTS was the issue and replaced it. That fixed the short GP cycle issue but also brought on a diff. issue. The gauge temp sensor now comes up to temp slower and reads 160 max when warm . I got part # 357 919 501A with the yellow band on the sensor. The old sensor had the yellow band too. Any ideas why my gauge now reads so low? Previous it read around 190 unless 10 degrees or colder out, then around 180.

Similar issue

I just replaced the sensor on my 98 Jetta and have a similar issue: I had the yellow band sensor, replaced it with the same unit.

Gauge comes on (reads minimum value) but doesn't move after 30 mins of driving. Did you ever come through this issue?

Have you cleaned the grounds near the battery?

It's also possible you got a bad sensor. I would clean the grounds then scan it with VCDS to see if the ECU is reading the same temp.

Tony

Is the thermostat stuck in a partially open position?
My 97 AHU (in my 95 Cabrio) was.
Start the engine in the morning when it is cold. Let it run a minute or so. Feel the radiator hoses but not right near the engine. If they have any heat apparent under those conditions, the coolant is flowing through the radiator and it shouldn't be, not yet anyway.