Greetings all!

Note to forum moderator: I am relatively new to the forum and I may have posted this in the wrong forum. Please move to the proper forum as necessary. Thank you!

I have a 1997 Honda Accord EX with 4 speed auto. I had a issue with the plastic inner fender coming loose and being ripped from the fender well. The right wiring harness was ripped from its hold downs and some of the insulation was abraded by the tire. I took it to the dealer (about a year or two old) and asked them to replace the harness. They supposedly repaired it. About a year go salt water and slush got into their so called repair and it started smoking. I patched the wires as best I could and I ordered a new harness from the dealer and replaced it myself. Everything is worked great except the AC. I used the electrical troubleshooting flowcharts, for AC issues, in the Helm Manual and found a defective a/c switch. I used a jumper at the a/c switch and still no a/c. I checked the a/c pressure switch, fan control units, fan and ac clutch relays and replaced both temperature sensors in the cooling system. I also checked the a/c diode. I ran point to point continuity checks on all wiring circuits. Everything checks out good. The the flowchart indicates the ECU may be defective. It suggest to swap the ECU with a known good unit. I found an ECU from a 1994 Accord LX with auto trans.

Will this ECU work in my 1997 Accord EX Auto? I know it came from a car with an auto transmission because I unplugged the unit myself. My first big concern is the difference between the LX and EX engine (Vtec in the 1997 and standard engine in the LX). My second concern is the three year difference in the ECU. Do they use different firmware in the rom chip?

Does anyone know of a test kit one may built/purchase to check the ECU? I removed the cover on the 94 ecu and everything appears good. No burns or hot spots. I know resistors and caps break down over time. I would like to test the unit prior to plugging it in. Has anyone used a company that works on ECU units? How expensive and do they have the ability to upgrade the firmware?

Sorry for the long post. Thank you in advance for your kind assistance!

 

No. You mentioned the first reason: it won't operate VTEC. Also, 94 - 95 Accords are OBD1 while 96 - 97 are OBD2. The ECUs are very different. Here's a Honda Service Bulletin showing OBD2 ECUs compatible with your car:

pennybaker(dot)com/ody/sb/SB%2001-012(dot)pdf

Looks like you'll need a 37820-P0H-L51 or -L52, or one of the replacements Honda issued to cure a trans problem. (I've never run across one of those replacement ECUs in the junkyards.)

Check eBay and junkyards. P0H ECUs aren't rare and aren't pricey. I bought one last year at my local U Pull and Pay for $50. Note that the 0 in P0H is a zero, not an "O".

 

I would have to echo Roader here.

no go with a 94. If your going to swap it out I'd try to hold out and find one for the same setup...

 

I should have known better. I friend needed a wiring harness for his Chevy and we found it with no problem. I found several accords, however, none were 1997 EX and I had to do the best I could from memory. The units look similar and made certain it was for a vehicle with an automatic transmission. What the hell it cost me about $20.00 for the wrong unit.

I found the Honda Part number from Majestic Honda a few minutes ago. I noticed the differences in the part numbers. The first five digits are the same. The middle three and last three are different. (P0B-A51) Stupidity on my part. I should have never gone there without a part number in my pocket.

Back the pull-a-part to see if I can find the right part. I was amazed the number of Accords and Civics with ECU still in the vehicle.

Thank you again for taking time to point out my errors!