I have a 91 Honda Accord Ex Coupe. About a month ago I changed out my oil pressure sensor because it was leaking once I did that a few days later my check engine light came on. I did the self diagnostic test and check engine light flashed a code 43 & 6. Looking up both codes (6 for the ECT sensor and 43 for Fuel Supply System defective or malfunctioning fuel supply system) I called the Honda dealership to get a specific on the code 43 and they told me it was for the O2 sensor. I went to Autozone and purchased both sensors (bosh for the O2 sensor) and replaced them a few weeks ago. This week is my time to drive and on Monday my check engine light came back on. I did another self test and got the same codes as before (43 & 6). I did reset the ECU by removing the backup fuse. The car drove good for a couple of days before Monday. Is there anything else that can be giving these codes? Do I have two O2 sensors on my vehicle (I replaced the one on the exhaust pipe under the car next to the catalytic converter)? If anyone has answer I would gladly appreciate it. Also I smell exhaust fumes on the inside of my car as well... Does that have anything to do with it? Assistant much appreciated... Thanks

 

Your car has only one O2 sensor. Return the other one (the 2nd O2 sensor started on the 1996 accords).

A code 43 is somewhat vague code. The O2 sensor was working properly, but likely giving the computer readings that are off. From your description, you have an exhaust leak that you need to trace. Watch this video:

The code 6 is something you should check. The engine coolant temperature sensor is under the distributor, has two wires going to it, and does NOT have a green plug. Check the electrical connector first.

 

I have already replaced the O2 sensor and the engine coolant sensor when I posted the thread. But I am still getting the error code 43 & 6. Is there anything else that can make this code appear? Also I just had my emission done and I failed due to high numbers on the CO and CO2 readings. What else could cause those readings to be high other than the O2 sensor? I've checked the electrical connectors and everything seemed to be fine (visually looking at them). Do I need to test them?

 

If the ECT was replaced and you are still getting a code then more testing should be done...be sure the wires are good all the way back to the ECM.....also please ref pic, red arrow is the ECT......as stated under the dist on the pass end of the head. EDIT: I know the pic is for a 5th gen but the 4th is in the same place.

If you are smelling exhaust fumes, need to find/fix/repair the leak. Depending on where the leak is, this can cause issues.