CCM thermistor issue

martlinel · Dec 15th, 2016, 14:34

I recently had a fault code re cabin temp etc. I have replaced the thermistor with one bought off eBay. No more fault codes except now I have one for air quality sensor which I'm not overly concerned about. However the heating in the vehicle still isn't working correctly . I have connected my icarsoft reader to see what the thermistor sensor was reading. It seems to automatically sit at 25 degrees. If I turn the heating up it does rise. If I turn the heating down to cold the temperature will reduce but the thermistor doesn't seem to register below 25 degrees even though cabin temperature is a lot lower. Do I have reset anything i.e. As a base line or anything, is it the air temperature sensor interfering with the fault( although I don't see how it would) or should I replace the thermistor again to see if that helps, I'm hoping it isn't just a case of resetting the CCM somehow.

cheshired5 · Dec 15th, 2016, 14:37

Cabin temp should rise and fall in line with your dial setting.
Something is wrong with yours.

IainG · Dec 15th, 2016, 15:01

Hi
There are quite a few different thermistors around, are you sure you have the correct type and value one.
Easy to test with an Ohmmeter when disconnected.
If you need a 10K one it will be 10K ohms at 25 deg C, etc etc
The values tend to be referenced at 25 deg C
If you have the wrong one it will not work correctly. There are also 2 different types, PTC and NTC as well as all the different values
Worth checking you have the correct one first.
Iain

Chris_Rogers · Dec 15th, 2016, 15:41

This is the correct one:

http://uk.rs-online.com/web/cpd/5288...hTerm=528-8558

But is the sensor grill clear and the sensor fan working?

martlinel · Dec 15th, 2016, 19:46

Thanks both I've checked the spec of the thermistor I put in and it appears to be the same. The little fan behind the the thermistor definitely works and is clean as I cleaned it all out when I soldered the new one in. I have ordered the other thermistors so will try those and see if that makes any difference.

VOLVOBOY · Jul 18th, 2018, 09:43

Hi.
How are you getting on with this ?
I have exactly the same problem.

Dec 15th, 2016, 14:34	#1
martlinel New Member Last Online: Mar 22nd, 2024 13:24 Join Date: Oct 2010 Location: Alcester	CCM thermistor issue I recently had a fault code re cabin temp etc. I have replaced the thermistor with one bought off eBay. No more fault codes except now I have one for air quality sensor which I'm not overly concerned about. However the heating in the vehicle still isn't working correctly . I have connected my icarsoft reader to see what the thermistor sensor was reading. It seems to automatically sit at 25 degrees. If I turn the heating up it does rise. If I turn the heating down to cold the temperature will reduce but the thermistor doesn't seem to register below 25 degrees even though cabin temperature is a lot lower. Do I have reset anything i.e. As a base line or anything, is it the air temperature sensor interfering with the fault( although I don't see how it would) or should I replace the thermistor again to see if that helps, I'm hoping it isn't just a case of resetting the CCM somehow.

Dec 15th, 2016, 14:37	#2
cheshired5 Premier Member Last Online: Dec 26th, 2021 13:42 Join Date: Dec 2013 Location: Crewe	Cabin temp should rise and fall in line with your dial setting. Something is wrong with yours. __________________ 2002 S60 SE D5 Manual 209000 miles

Dec 15th, 2016, 15:01	#3
IainG Premier Member Last Online: Today 07:53 Join Date: Apr 2013 Location: Plymouth	Hi There are quite a few different thermistors around, are you sure you have the correct type and value one. Easy to test with an Ohmmeter when disconnected. If you need a 10K one it will be 10K ohms at 25 deg C, etc etc The values tend to be referenced at 25 deg C If you have the wrong one it will not work correctly. There are also 2 different types, PTC and NTC as well as all the different values Worth checking you have the correct one first. Iain

Dec 15th, 2016, 15:41	#4
Chris_Rogers VOC Member Last Online: Apr 10th, 2017 16:55 Join Date: Jan 1970 Location: South Kent Coast	This is the correct one: http://uk.rs-online.com/web/cpd/5288...hTerm=528-8558 But is the sensor grill clear and the sensor fan working?

Dec 15th, 2016, 19:46	#5
martlinel New Member Last Online: Mar 22nd, 2024 13:24 Join Date: Oct 2010 Location: Alcester	Thanks both I've checked the spec of the thermistor I put in and it appears to be the same. The little fan behind the the thermistor definitely works and is clean as I cleaned it all out when I soldered the new one in. I have ordered the other thermistors so will try those and see if that makes any difference.

Jul 18th, 2018, 09:43	#6
VOLVOBOY Lazy Member Last Online: Today 10:50 Join Date: Mar 2007 Location: HORLEY	Hi. How are you getting on with this ? I have exactly the same problem.

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