Exhaust Gas Recirculation (EGR) Control
The TCCS system controls the EGR function either directly or indirectly. Verify EGR function control by referring to Figs. 1 through 10 in "General Description" section. Some model, year and engine/transmission applications will determine if the EGR function is directly controlled. The EGR temperature sensor on some applications is used only on California models.
EGR is controlled by the ECU based on coolant temperature. The ECU controls operation of the EGR system by controlling vacuum signals transmitted to the EGR valves. For complete description, diagnosis and testing, refer to ``Emission Controls.''