Just bought a 91 Accord EX Sedan to use as a daily driver to and from work. The CEL came on 2 days ago and I checked the code and got a 43. I've read other posts where people were experiencing rpm and acceleration issues but I have not experienced any thus far. After the light comes on I do not notice any change in how the vehicle drives, the only problem that I see is the fuel consumption. I've wasted almost half a tank and only gotten about 100 miles out of it......just doesn't seem right on a Honda. I think it might be the O2 sensor, but that again is just from reading different posts...if that may be the problem...where is the 02 sensor located and is it a repair that I can do myself? I hope so.

 

My Haynes manual doesn't list a code 43. A code 1 indicates an O2 sensor problem.

The o2 sensor is located on the exhaust manifold. Shouldn't be that hard to replace, just unscrew it (with manifold warm to prevent stripped threads) and put in a new one. Haynes says disconnect the battery, probably a good idea if you don't want to risk hurting the ECU, but it might put your radio into anti-theft mode, requiring you to enter the radio reset code.

Are you sure you are reading the code right? If there is a long pause, it might be two separate numbers.



For reference, my 91 Lx gets about 300 miles to the tank driving city with some highway, and 400+ driving mostly highway.

 

Code 43 is a kind of catch-all for a situation where the fuel rate combined with the O2 sensor reading doesn't really add up. The ECU can't "blame" one particular measurement but something's not right.

I think(?) in 91 the exhaust manifold is 4-into-2, then the exhaust combines into ONE pipe down under the oil pan. THAT's where to look for the O2 sensor. Probably just aft of the oil pan, before the catalytic converter.

 

Thanks for the responses. I did infact check 2-3 times to make sure theat i was reading the code correctly. There is 4 long blinks followed by 3 short blinks...then a long pause and then it just repeats itself.

I have in fact read where it is a "catch all" so I am planning on testing the O2 sensor next weekend. One of my concerns is that I am not sure if it has more than 1 sensor, some threads I have read talk about the vehicle having a primary and secondary O2 sensor...which just complicates things to me because I wasn't sure where the 1st sensor was.

I've also looked at some online catalogs to see prices...the range from 30-60 bucks and the it jumps to 170+ bucks. I don't understand the price difference other than the more expensive is called a "kit" and is made by AC Delco.

 

Your 91 should only have 1 O2 sensor. Beginning in 1996 they were required to put another one AFTER the cat, just to measure whether the catalyst was working.

Look for Denso sensor. I think they make em for Honda in the first place.

 

Hmm...I'm working on my exhaust now. I changed out my muffler assembly today and plan on changing out my front pipe ("down pipe") within the next few days. That said, think the sensor is underneath the heat shield (on the front) not near the CAT. I didn't notice it looking around down there.

I'll see how accessible the sensor is (and where it is) while doing this and let y'all know. I think I might need to remove the heat shield anyway...

Unrelated note:
Oh, and that code 43 thing is good advice. That Haynes manual really isn't useful I found. I swapped out my axles recently and just abandoned the manual altogether...more trouble than it's worth.

I have a whole DIY post on axle swaps ready, with pictures, but just need a mod to get back to me about it *cough cough*.

 

You mean me?
We used to have a large quota for private-messages. When they went to the new forum software, my PM box is suddenly 400% over-full. Cant read, can't delete... etc. So, I'll have to figure out how to delete my PM box without reading it. Fun...

 

Well......the ECl is still coming on because I haven't changed the sensor yet, don't plan on doing it until next weekend. However, this morning I get in the car and on my drive to work I notice that the D4 light is flashing on the dash board...of course the first thing I think is What Now!!

I went through the whole jumpwire to get the code scenario and I still get the code 43 from the ECL light but the D4 light flashes alot of codes. I let them run throught 2-3 times to make sure I captured the codes accurately.....and here they are:

ECL: Code 43
D4 : Code 1
D4 : Code 2
D4 : Code 3
D4 : Code 5
D4 : Code 7
D4 : Code 8
D4 : Code 14

Man I am beginning to think that I've been had.....

 

This is more of a General Tech thread, so I'm gonna move it there.

If you don't get much, post again (in Gen.Tech) with a title that says something about the tranny codes. Unfortunately, I'm not much of an auto-tranny guy.

 

Well im working on a neighbors 91 accord with the same problem. s light flashes all the time regardless what gear its in. At 50 mph the car doesnt have any power, from the posts ive read its the sport shift not working properly, i jumped the obd 1 and got error code 43 which i see makes no sense. i do have a thread for you folks that will absolutely help i believe
Honda Electronic Transmission Problem- Troubleshoot, Inspection, Repair, Replace.
it will show you how to trouble shoot all these issues and then some its quite a bit of work but im sure you DIY guys will be able to do it, JUST MAKE SURE you take care of your regular codes first it says before trouble shooting it! Please respond if you find anything and i will do the same as i am starting to dig into it now