Golf III AFN: Temperature Sensor Problem

Hello!

Since I've owned the Golf (about 1 year), I've been having a problem with the 4-pin temperature sensor.

I always get this error code when I read the error logs. The exact definition of the error isn't clear, and it only appears intermittently. Because of this, I installed a new sensor. However, I keep finding the error code in the memory.

A sensor with a blue ring was already installed, and I've installed another one with a blue ring! However, I'm not sure if it's the correct one, as I don't know what the previous owner might have done. Apparently, there are also some with a yellow ring.

I'm using a Tunline chip, and I bought the engine control unit (ECU) used from a colleague. He didn't experience many issues with it before, but I have. One possible cause could be this sensor, due to a richer fuel mixture.

So far, I have only visually inspected the wiring and the pins.

Has anyone ever experienced something similar with this symptom?

Best regards, Chris.

Does anyone have any ideas? I don't want to spam this thread!!! Sorry for the double post.

Find out the VAG part number for your temperature sensor and which part number is the original one for your car. Since these parts come from different suppliers, don't rely too much on the color. Someone here in the forum or a trusted mechanic should know the correct part number.

Then you should check the wiring between the sensor and the control unit. Look for any signs of abrasion or damage, and then use a multimeter to test the connections. While doing so, also try wiggling the cable to see if that affects the readings.

If the soot doesn't disappear, reinstall the original control unit and check the target values using VAG-COM. This means verifying if the temperature values are reasonable, if the fuel injection quantity and boost pressure are correct, etc. If you're not sure how to interpret the data, please post a log file here.

You can find the target values and instructions for creating a useful log in the technical articles.

Good luck!

Okay .

First of all, thank you very much. I used Autodata to check the pins, and sometimes I had power, and sometimes I didn't. The problem was a cable that was chafed, and then it was shorting to ground! That's why it was intermittent.

Best regards, Chris.

Okay, I'm glad you found it.