Circuit Opening Relay

Circuit opening relay controls fuel pump circuit. The Electronic Control Unit (ECU) receives an input signal at STA terminal when engine is cranking. Starter signal is also applied to terminal STA of circuit opening relay.

Starter signal energizes circuit opening relay during cranking. Circuit opening relay then provides voltage to fuel pump or fuel pump relay. Celica Turbo, Cressida, MR2 Turbo and Supra use fuel pump relay.

On all models except Camry 2.2L, Celica, Corolla, MR2, Paseo, Supra Turbo and Tercel, fuel pump switch in airflow meter provides ground for circuit opening relay. On all other models, circuit opening relay is grounded by the ECU through the FC terminal.