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.