Oh, I just noticed I hadn’t put any text into this post. Sorry for that. I found out, actually, noticing someone had specifically requested this post, probably to find out a little something about the fault code P0116. All he got for his trouble was a Hello world message.

So I thought I should write something from my experiences with this fault code, rather than just delete the post.

I first encountered the fault code P0116 on out Saab 9-5 Biopower, an 2006 model with 250.000 km on the meter. I later saw it on a neighbors Saab as well and even on my bonus father-in-laws Saab, so I think it’s a common enough error code on older Saabs.

Googling it led the quite a few tips, the best one I didn’t follow immediately, but should have. It read something line:

This error is raised either because of a faulty coolant temperature sensor or an old, tired thermostat. As each is like $ 15 and it’s always going to be the one part you don’t replace that’s faulty, it’s best to change both at the same time.

This turned out to be the best advice I didn’t follow. I only replaced the sensor, and a few days later the engine light turned on with the same error code.

A while later, I changed the thermostat as well, and the light has stayed off ever since. After the new thermostat the coolant temperature behaves much better as well.

I changed the thermostat on my neighbors car as well a month ago, after she had had the shop replace the sensor three (!) times. Same problem with weird coolant temperatures before the replacement, good behavior and no engine light after the replacement.

Changing the sensor takes 20-30 minutes, changing the thermostat takes about an hour, so I think the benefit of replacing these two items definitely outweighs the bother and cost doing it.