Code 43 - Fuel Supply System
- If referred here from CODE 1, go to step 2). If Code 43 exists, turn ignition off. Remove BACK-UP fuse (7.5-amp) from underhood fuse/relay box for 10 seconds to reset ECM. Warm engine until cooling fan comes on. With transmission in Neutral, raise engine speed to 3000 RPM and hold for 2 minutes. Retrieve codes. If Code 43 does not appear, problem is intermittent. Inspect for poor connections at ECM, HO2S, and wiring harness connectors.
- If Code 43 exists, turn ignition off. Connect ECM Test Harness (07LAJ-PT3010A ) between ECM and ECM harness. See Figure . Wait 2 minutes. Install jumper wire between test terminals A6 and A26. Turn ignition on while measuring voltage between terminals D14 (+) and A26 (-).
- If 0.1 volt or less exists as ignition is turned on, go to step 5). If more than 0.1 volt exists as ignition is turned on, unplug HO2S connector. Measure voltage between HO2S wiring harness connector Green/Blue and White/Red wire terminals.
- If voltage is greater than 0.1 volt, replace HO2S. If voltage is not greater than 0.1 volt, repair open circuit in Green/Blue or White/Red wire between HO2S and ECM connector.
- If voltage was not greater than 0.1 volt as ignition was turned on in step 3), unplug HO2S connector. Measure voltage between test terminals D14 (+) and A26 (-). If voltage is greater than 0.1 , replace HO2S. If voltage is not greater than 0.1 volt, unplug connector "D" from wiring harness. Measure voltage between test terminals D14 (+) and A26 (-). If voltage is greater than 0.1 volt, repair short in White wire between ECM connector and HO2S. If voltage is less than 0.1 volt, temporarily substitute known good ECM, then retest system.