Hello, okay, I had to go over your case again since it's been a couple weeks or so. The Check engine light test you mentioned is a good clue. You are correct, when you turn the key to the on position, engine off, the check engine light should come on for a few seconds. If it doesn't that means that the ECM is either partially or fully not being powered up. It doesn't necessarily mean the ECM has failed, it just means for now, we know that it's not powering up. The Honda main relays are known for going bad, especially the earlier 2000s models. The fact that you were able to pull a code out of the ECM means that it was able to communicate with the scan tool. That tells me that at least part of the ECM was powered up enough to communicate on the data bus to your scan tool. I would be curious to see if you can read any live data with your scan tool, depending on the type of scanner you have. I will pull up some wiring diagrams and the location of the ECM so you can check it for power. It looks like from your folder I had pulled out the flow chart for diagnosing the Throttle control unit, which was for the U0107, but now that the check engine light is not coming on, the code is probably a result of the ECM being down and not the cause. And actually, looking at the ECM diagrams, the Throttle Actuator Control module relay is directly powered up by the PGM FI main relay 1. Thats one of the relays that seems to fail often in these vehicles. I remember replacing many of them back then. It's a large double relay up under the driver's side dash. It should have 2 connectors to it. Do you know if the shop it was at had tried replacing this relay, was there anything on the repair order about having changed it out? The PGM FI relay 1 powers up part of the ECM, the fuel injectors and a junction port that supplies power to a bunch of other components, the PGM FI 2 relay powers up the fuel pump. And I'll post diagrams of all these for you to see.
You can see by the diagrams 2 and 3 how much these relays are responsible for. And it might have been that part of the ECM was powered up, just not the entire module. Both the PGM FI relays are one unit. It's pretty easy to find, it will be up to the left of where your left foot is.
Ok it looks like they are located in this multiplex fuse relay box (diagram 4). In the older vehicles they were separated and just bolted to the body of the car. So, with the key Off, I would pull out the number 1 first since it powers up the number 2 relay. If they are cheap enough, I would try replacing them and see if that's the issue. I will also post the ECM connectors and location so you can check those pins for power first if you would like to do it that way.
Diagrams 4 and 5 show the ECM location and connector letter A, B, C, D, E,
Each diagram after that shows each connector with its letter and then followed by 1 or 2 pages of the pinout value each wire should be, with the connector letter at the top, so you can check each one and know what should be there with the key On. This way you'll know exactly what is missing for power inputs.
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Friday, May 26th, 2023 AT 11:42 AM
