15C temp switch for CIS
 

So, I had been thinking that my 15C temp switch (mounted in top corner of the passenger side cam chain cover) was faulty. Bentley says it is a normally open switch that closes (goes to ground) when the temp gets above 15C. When I tested mine in-car, it was open even when the car was warmed up. I ordered another one from Tom Butler, but when it came it had the same behavior - it seemed to be always open even when I heated it. I told Tom he sent me a faulty sensor, so he checked other sensors he had in stock and found they all did this. But, if he cooled it in ice water, it closed! So it would appear that my 15C sensor has been functioning all along and Bentley is wrong.

Can anyone else confirm this? Is Bentley wrong? Does the 15C switch close below 15C and is open above?

Thanks.

Geoff

Do you mean the thermo time switch? Mine is in the driver's side cam cover...

The TTS provides a ground path for the cold start valve, but the CSV is only energized when cranking, and only until the built-in heater in the TTS warms it up above the cutoff (allegedly stamped on the body) - which takes about 7 seconds at -20, apparently, and as little as a second or two above that - if the thing is even providing ground at all at your current ambient temps.

When the Germans say "Cold Start Valve", they're thinking of ice racing on frozen glaciers, it seems... :)

Hello Geoff,

Yes, that is one of several errors in the Bentley manual. If the system is working properly, you should see a constant duty cycle at the test plug for the first few minutes, then a fluctuating needle once the system goes closed loop. ******** sell an alternative BOSCH CIS lambda switch (Super Switch) that closes at a higher temperature for engines that never see temps below 59F. Unfortunately, good CIS lambda info is thin on the ground.

Ok, so the purpose of the 15C switch is to allow the O2 sensor readings to stabilize before going into closed loop mode? Did you *** out the vendor, or does Pelican do that? I googled for BOSCH CIS lambda Super Switch but didn't find anything.

Thanks.

Geoff

Just wanted to confirm the my 15 c switch on the passenger side was the same closed until around 20c and then opened. I spent about an hour looking through the forum before I read this one. So I guess it’s a mistake in the Bentley book page 240-28

its already a well known bug in the bentley manual