6-Cylinder & V8
The CTS is installed in the number 6 runner of the intake manifold on 6-cylinder engines and in the number 8 runner of the intake manifold on V8 engines.
When air/fuel mixture temperature is below 60°F (16°C), the switch closes. This prevents EGR timer and EGR valve operation. When air/fuel temperature is above 60°F (16°C), the switch opens. This again allows the EGR timer and EGR valve to operate.