morpheus5039
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- Jun 6, 2007
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Imported E34/E32 from Japan have 2 sensors in the exhaust systems. 1 before the catalytic converter and another just after it.The one before is the Oxygen Sensor which lets the ECU detect the oxygen level to adjust the air/fuel ratio.The one after is the temperature sensor for the catalytic converter to detect its temperature (which is only available in Japanese E34 only). It is used to prevent overheated cat-converter from burning grass, etc nearby.There is a relay (thermo switchgear) under the backseat which control the temperature sensor. When the temperature sensor or the relay mulfunction, "catalyst" will show on the check control display.It is useless in here, it was fitted in Japan just because of the Japanese regulations. No other country using it too. So it is OK to throw away the temperature sensor when you modify your exhaust system (using custom piping) without making a new bung for the sensor.To avoid the "catalyst" comes out from the check control display, simply pull out the thermo relay under the rear seat.
The writing on the label may not be the same. For my car, the part numbers are: 61 358 365 846 , with "ABS" written on it. (It's not ABS relay as it is inside the front fuse box)How do I find out?http://forums.bimmerforums.com/forum/showpost.php?p=17119062&postcount=40This applies to owners who convert their E34 to M50/M50TU from M20 using Japan Halfcut/Wiring. Sometimes sensors do not come along with the car.There is only one big and long yellow relay under the rear seat.
