2003 Honda accord ex-l 4cy 4 door automatic 75k

I just recently purchased this vehicle private party and It wont pass emissions. Not getting any information form the computer. Honda told me that the ECU needed to be replaced and wanted 1100 dollars to do it. I replaced the ECU with a used one taking Hondas word for it and come to find out that the ECU was fine. The problem seems to be a wiring issue as I can tell that a couple of wires have been rigged together. Im guessing that whoever fixed the car when i was salvaged was not a mechanic by any means...duct tape was covering all most all of the wires. The strange thing is that everything electronic inside the car works perfectly ie; GPS, Climate control, Moonroof power seat, windows, cruise controls, windows, door locks, so I can assume for the MOST part the wiring was done correctly.

My question is simply is there something simple that I can check for on the OBDii port to see if it is missing a wire or something? Does anyone have access to a diagram for this? Im not sure what else to do...I cant trust Honda to fix it and Im not sure who else to call. Are there still mechanics out there that will actually LOOK at the problem and try to fix it???? or are they just give me the same half *** answers honda has been giving me...

Any help would be very much appreciated....I'm very lost

 

You will have to check the wiring. Not all of the pins are used in the 16 pin connector.

I know there will be one pin with 12V and another one that should have ground.

The other pins are for data reading/transfer.

I don't have an 03 wiring diagram, so I don't know how much more specific help I can provide.

You will have to check the wiring. See if there is continuity between the pin on the DLC and the specific pin at the ECU.

A honda accord shop manual will help out immensely.

 

Thank you for the help, I will get a manual and check the wiring.

The one thing I'm not sure about is the when I swapped the ECU out, I never paid honda to flash the new one to make it work with the chip inside the key which means the car would do everything except start (no injector pulse). I ASSUMED that i should still get diagnostic information from the unit but I'm not sure about that.

 

Yes you should get scan tool access with a non programmed chip key. You have to be able to access it with a scan tool or else you wouldn't be able to program the key using the scan tool.

Are you sure that the scan tool isn't the problem? Some OBDII scanners refuse to talk to certain cars.

 

Thank you for the information...

I'm not sure about much to be honest. deq (emissions for portland) tried two of them and got nothing on the old computer. Honda also got nothing. I took the new computer to auto zone and got an error. They said that there is voltage to the scan port but it just wont communicate. And I confirmed that there was voltage there, but not too sure where to trace the rest of the wires to at this point. Is it just one harness from the ECU to the scanner port?

Thanks

 

On the online manuals thread in the DIY section, you can download an acura tsx shop manual. That car is similar to the accord.

For the TSX here are the wire colors for the pins at the DLC.

16 wht/grn Hot 12V
14 gry Immobilizer
12 red/wht ECU E30
09 brn ECU E29
07 blu ECU E23
05 blk Ground
04 blk Ground

If the wire colors match up you can check for voltage from 16 to a ground. For 04 and 05 test for continuity to a good ground point. I try to find some a bolt or some bare metal to touch my volt meter to ground.

14/12/09/07 pins are where you can test for continuity from those pins on the DLC to the ECU pins. You will have to get a pinout of the ECU on your accord. The E30 would be the E plastic plug and 30 is the pin number. Don't forget that is for the TSX, so the accord may be different.

 

Thank you so much...When I get the chance I will look at that!