Temp gauge erratic
 

Hey everyone, I'm wondering if anyone has experienced this problem? My '93 940 wagon's check engine light came on the other day and it came up as a bad temperature control module, which I was able to replace w/o needing to remove the intake. I did have to remove the ETM, of course, and took advantage of that to clean it and replace the gasket. So, now the check engine light is off, but my temp needle falls under acceleration after about 45 mph and vacillates back and forth from the straight up and down to showing nearly nothing the rest of the time. The motor isn't heating up, everything else seems to be okay and the car runs great, except I still have a rough idle, as well as, a slight stalling when I come to a stop with the a/c on, which I was hoping would go away with this repair and ETM cleaning. Any ideas?

the temp gauge is on its own sensor, seperate from the one thats used by the ECU and ICU. the temp gauge sensor is in the same row under the intake manifold, and has a single pin. its possible you knocked this loose or something?

as far as rough idle, and stalling, I'd start with the steps listed here...
https://www.volvoclub.org.uk/faq/Eng...eSymptoms.html

Thanks for the reply. Yes, it's possible that the plastic connector got slightly damaged previously and may be cracked, which is something I had also been considering too.

Thanks for the link too...

"Temp. Control Module"? You mean the Coolant Temp Sensor? Did you replace it or just clean it? I don't think just cleaning it is enough. Get a good OEM sensor, it's important!


That sensor shouldn't affect idle/stalling once the motor is warm but who knows how screwed up it is. The gauge sensor is indeed independent and likely it's a matter of loss of contact. BTW, rough idle and stalling doesn't add to running "great" in my book...