505 L4-1971cc XN (1983)
Exhaust Temperature Sensor: Description and Operation
The catalytic converter oxidizes the exhaust gasses flowing through it. As a result, carbon monoxide and hydrocarbons are transformed into carbon
dioxide and water vapor.
Peugeot 505 models equipped with the Lambda (exhaust gas oxygen) sensor have a dual bed catalytic converter. The first bed contains a three-way
catalyst which reduces nitrogen oxides in addition to oxidizing carbon monoxide and hydrocarbons. The second bed contains a two-way (conventional)
catalyst which further oxidizes the carbon monoxide and hydrocarbons.
EXHAUST OVERHEAT WARNING LIGHT
The overheat warning light comes ON when a catalytic converter overheat condition exists.
The warning light system consists of a thermo switch which is located close to the catalytic converter. When the heat shield mounted sensor temperature
exceeds approximately 200°F, a circuit will be completed to the ``EXH TEMP'' warning light on the instrument cluster.
