9000 CS L4-2290cc 2.3L DOHC Turbo EFI (1996)
Exhaust System Temperature Indicator: Description and Operation
Cars for certain markets are equipped with a monitoring system for catalytic converter overheating. The system consists of:
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Temperature sensor 417
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Electronic relay 415
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Warning lamp 471
When catalytic converter temperature reaches 825 +/- 25°C, the warning lamp lights up and remains on until the temperature drops by about 10°C.
When current (+15 circuit) is applied to relay pin 1, the warning lamp is grounded and lights up for about 3 seconds. It does not come on again unless
the temperature of the three-way catalytic converter exceeds the set limit.
As the temperature rises, the current flowing between pins 3 and 4 of the temperature sensor changes. When the resistance of the sensor changes by a
sufficient amount, the relay function is activated and the warning lamp lights up.
Similarly, the warning lamp goes out when the temperature drops or when current (+15 circuit) is no longer applied to the relay, i.e. when the ignition is
switched off.
