[yurtesen]

It is curious. I would have expected the climatronic to adjust temperature based on vent temperature sensors and use the G89 sensor for fresh air temp.

AFAIK there is no calibration for this sensor. If system thinks there is a fault on G17 sensor, then the G89 sensor may be taking over. So it may not matter if you change the sensor if this is the case.

Use VCDS to read error codes and check directly the values of G17 and G89.

A skoda manual says G17 sensor can be tested using multimeter by measuring resistance values. I am not sure if they are same for Golf MK4. But you can at least compare output from your 2 sensors if they are same or not.:

Temperature Specified value -30 °C approx. 18265 Ω 0°C approx. 3300 Ω 20 °C approx. 1184 Ω 50 °C approx. 359 Ω

 

[yurtesen]

@djhowie You can also compare outputs of your sensors between themselves to see if they work exactly same. I am not sure if Skoda values apply to VW sensor but I am guessing probably yes. It may as well be that the sensor wire has a fault and system defaults to using G89 (and maybe that is faulty too?) You should read the values using VCDS and compare with outside temperature shown on dash.

The dash coolant temperature indicator is not accurate. In my car it shows 90 when it is between 80C to 100C. That said you need to use VCDS to read the actual value from instrument cluster or the engine controller.

This should bother you, as your car will use more fuel if engine controller thinks it did not warm up and also idle RPM will be raised. Your thermostat may be stuck open or the temperature sensor is faulty. Check the temperature using VCDS before you start the car, it should read near outside temperature. Can perhaps compare with oil temp also. You can also see if your radiator pipes get warm quickly when you start the vehicle.

I feel you need to give an autoscan with VCDS and check what errors you have. That may be a good start. Do that first then come back with results.

 

[yurtesen]

@djhowie if you had bad negative connections, I would expect you to have a bunch of codes recorded. There is always a bunch of stuff sharing them. Also the computer is normally able to catch sensors which have bad connections.

That said a single puddle shouldn't melt down your car unless you meant that you parked your car inside ocean for a month?

The RPM rises in several levels, when I start the car cold it does 1100 then goes down while warming up to 1000, 900, 800...until 650 if I am not mistaken.

 

[yurtesen]

You seem to be checking values from instrument cluster. Can you check your climatronic G89 sensor value also (because that is what you need to check actually for your problem)? Also G17 should be there too? Is it same as in instrument cluster?. As you were complaining about air conditioning, you should prioritize sensor values of what climatronic sees.

Did you check the G17 with ohm meter? I think the values should be

-30⁰ C​

Approx. 18265Ω​

0⁰ C​

Approx. 3300 Ω​

20⁰ C​

Approx. 1184 Ω​

50⁰ C​

Approx. 359 Ω​

​

But for all intents and purposes you could measure the sensor and also compare from the climatronic input pins to see if it is same or not.

The V71 recirculation flap can effect the effectiveness of your A/C also. In very hot weather, climatronic automatically would sometimes recirculate inside air because it is easier to cool down already cooler inside air compared to getting hot air from outside. I think this is a common problem as the gear inside the servo gets cracked in that servo often.

The fuel temp sensor is not there for esthetics and actually effect something ( whether you feel or not ). -> https://www.myturbodiesel.com/wiki/fuel-temperature-sensor-injection-pump-seal-replacement/

 

[yurtesen]

@dhowie It is simple to measure and no need for fridge. I assume you have one at home now as you changed old one?

If your home is around or little warmer than ~20C. You can simply measure it and expect under 1180ohms. If sensor is bust and incorrectly showing ~8C then it would be above 1180ohms. Just be sure to not warm it up with your hand! Let us know if sensor is fine.

SSP 208 says: http://www.volkspage.net/technik/ssp/ssp/SSP_208_d2.pdf

From both sensors the one with lowest value is utilized for temperature flap operation.

By the way, temp displayed on panel (in some labels it says calculated temperature) does not update unless you drive the car I think. The outside temperature is what G17 reads currently.