for all with BMW imported from Japan

[shogun]

Japanese spec. BMW (of the older generation like E34/32) have a temperature feeler at the end of the cat. If the temp exceeds 800 degree Celisius, there will be a warning in the check control and the gong will give alarm.
I just helped someone with a 1989 E32 750iL in Canada who had a permanent warning, even when the cat was cold. gong gong gong gong gong...........

Going thru the files I found that there is a thermo switch under the rear seat (E32). Asked him to pull K13 and the problem was solved. The thermo switch is defective and always gives alarm.
With this also the other typical japanese starting procedure tests are gone, that means in the check control
-see owners manual
-cat
-gong test

Just in case you have such a prob, look for this yellow thermo switch in your car, in the E32 it is the one on top of pic one (yellow relay)
http://www.bimmerboard.com/members/bigbimmer/CIMG0163.jpg
http://www.bimmerboard.com/members/bigbimmer/PIC_0028.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0029.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0030.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0031.JPG

Another solution:
the cable white/purple/yellow goes from this module to another plug on pin 20
to the CCM. If you cut off this cable and connect it to ground, that has the same effect.

[rob101]

Japanese spec. BMW (of the older generation like E34/32) have a temperature feeler at the end of the cat. If the temp exceeds 800 degree Celisius, there will be a warning in the check control and the gong with give alarm.
I just helped someone with a 1989 E32 750iL in Canada who had a permanent warning, even when the cat was cold. gong gong gong gong gong...........

Going thru the files I found that there is a thermo switch under the rear seat (E32). Asked him to pull K13 and the problem was solved. The thermo switch is defective and always gives alarm.
With this also the other typical japanese starting procedure tests are gone, that means in the check control
-see owners manual
-cat
-gong test

Just in case you have such a prob, look for this yellow thermo switch in your car, in the E32 it is the one on top of pic one (yellow relay)
http://www.bimmerboard.com/members/bigbimmer/CIMG0163.jpg
http://www.bimmerboard.com/members/bigbimmer/PIC_0028.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0029.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0030.JPG
http://www.bimmerboard.com/members/bigbimmer/PIC_0031.JPG

Another solution:
the cable white/purple/yellow goes from this module to another plug on pin 20
to the CCM. If you cut off this cable and connect it to ground, that has the same effect.
i've seen this myself i always wondered why my friends jap import 525i had a temp sensor in the cat and mine didn't. any idea what the reasoning behind that was?

[shogun]

Bill R. wrote once in 2004:

Japan was one of the few markets that required a temp sensor on the back of the cats to warn you when the cats are overheating... this isn't a bmw only thing, i'm pretty sure its all cars in the japan market, I've seen a number of gray market toyotas and nissans with the same temp sensor on them. I suspect if you look at japans equivalent to the epa pollution rules for cars you'll see that theres a requirement for cat temp sensors as a safety device. A badly overheating cat will glow cherry red and ignite any paper or grass etc that its parked over.
And here's the section of the agreement where they decided that imports from the US didn't have to have them anymore.
http://www.bimmernut.com/~billr/images/catwarninglight.jpg

[rob101]

Bill R. wrote once in 2004:

Japan was one of the few markets that required a temp sensor on the back of the cats to warn you when the cats are overheating... this isn't a bmw only thing, i'm pretty sure its all cars in the japan market, I've seen a number of gray market toyotas and nissans with the same temp sensor on them. I suspect if you look at japans equivalent to the epa pollution rules for cars you'll see that theres a requirement for cat temp sensors as a safety device. A badly overheating cat will glow cherry red and ignite any paper or grass etc that its parked over.
An here's the section of the agreement where they decided that imports from the US didn't have to have them anymore.
http://www.bimmernut.com/~billr/images/catwarninglight.jpg
yeah i figured it was to detect overheating and thus prevent damage of the cat, Hmmm thats a good way to spot grey import bimmers. No offense but i am not a fan of the quality of bmw that gets imported into this country from japan.

[shogun]

That is not the point.

As Bill R. said:


A badly overheating cat will glow cherry red and ignite any paper or grass etc that its parked over.

I have seen cars burning parked with a hot cat on grass.