ECU question... CEL Help

[psycho_freke]

My father has a '92 Integra LS (automatic) that's throwing a code 41. I tried going through the troubleshooting procedures in the service manual and it's looking like it may be the ECU. I need to test that theory with a good ECU to see if the light goes away, but the only one I have is an OBD1 P72. Can we run his Automatic LS off of the P72 (manual transmission) long enough to see if the code goes away? I know his is a P74 or P75 and I'm not sure about trying this method with his being an automatic. The only other OBD1 ECU I have is a P06 (manual).

[*EFilliated*]

im pretty sure manual ECUs do Not start Automatic cars

[turbob20]

code 41 is heated oxygen sensor should be 4 long flashes and 1 short.

[psycho_freke]

code 41 is heated oxygen sensor should be 4 long flashes and 1 short.

Yes I know... since I had a spare O2 sensor laying around I gave it to him to try and it didn't fix it. We did the diagnostics on pages 11-56 through 11-58. We came up with battery voltage between Yel/Blk and Orn/Blk, and the flowchart pointed us to the ECU terminals. When we followed the flowchart it took us all the way to "Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM."

As you know, most of us don't have a spare ECU sitting in our back pocket. That's why I was hoping the P72 would start it.

[psycho_freke]

My train of thought here is that if it would start his car (not run it, just start it), we could then check the CEL (I'm sure there would probably be one just with using a manual ECU) and see if the code 41 goes away. If it does, then we know he has to replace the ECU.

[Tech5]

sounds like a wiring issue

[psycho_freke]

sounds like a wiring issue

Checking the wiring all the way back to the ECU is part of the flowchart, and if I had found a short or broken wire, the flowchart should have pointed us in that direction. He's decided to buy an ECU when he gets paid.

[turbob20]

just cause you had an oxygen sensor around dont mean its still good. the elements of the weather or anything could change that thats why they come new with a cover over them!

[psycho_freke]

just cause you had an oxygen sensor around dont mean its still good. the elements of the weather or anything could change that thats why they come new with a cover over them!

Replaced with a brand spankin' new one. Still throwin' a code. ECU is on it's way. Found out from him that he's had a couple other issues as well since he put that ECU in his car. This is his second ECU. The first was killed when the heater core leaked all over the damn thing. I also don't see how weather elements would've affected that O2 sensor when I just pulled it out of the exhaust about a week prior to giving it to him and kept it inside the cabin of the vehicle.

[YoItsCarlie]

since you already know there is a water issue, you may want to check all connections. look for anything that is not shiny metal.

as far as oxygen sensors go, as long as you use any ecu that has a 4 wire o2, you can trouble shoot. you will not be able to drive on a civic ecu. it will only have 2nd and 3rd gear. you can get away with an automatic accord ecu. they had transmission controllers up until the obd2 switch.