California vehicles only To EFI Main Relay Oxygen Sensor Oxygen Sensor Heater Check Connector E1 VF1 TE1 ECU VF TE1 OX HT E1 ① There is no voltage between ECU terminals VF and E1. Check that there is specified voltage between ECU terminal VF and body ground. OK BAD Check wiring between ECU terminal E1 and body ground. OK BAD Repair or replace. Try another ECU. Check for suction of air into exhaust system. OK BAD Repair air suction. Check for air leak from air intake system. OK BAD Repair air leak. Check spark plugs. OK BAD Repair or replace. Check cam position sensor and ignition system. OK BAD Repair or replace. Check fuel pressure. OK BAD Repair or replace. Check injectors. OK BAD Repair or replace. Check cold start injector. * OK BAD Repair or replace. Check air flow meter. OK BAD Repair or replace. ② Check operation of oxygen sensor. OK BAD System normal. Check wiring between oxygen sensor and ECU connectors. OK BAD Repair wiring. Replace oxygen sensor. * Rich malfunction only