Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector.
Connector & terminal
(B135) No. 8 — (E23) No. 3:
(B135) No. 9 — (E23) No. 1:
Is the resistance less than 1 Ω?
Repair the open circuit of harness between ECM and front oxygen (A/F) sensor connector.