Where can a person find a used ECU at a reasonable price? I've got a 2000 Civic HX that is telling me after a lot of diagnostic testing (and replacing EGR valves, etc.) that the ECU (P2N) is bad and I'd like to find a replacement. I'm not trying to get higher performance. My main goals are high mpg and no CELs. Then, once I've got one, will it be just plugging it in and driving, or will I have to take it to a dealer or performance shop to get it programmed or whatever? Thanks.

 

ECUs do go bad, but it's rare.

What code(s) is thrown and what have you done so far?

 

Have you cleaned the EGR passages in the manifold and the head? That's the cause of most EGR problems on the HX's.

The 2000 ECU is just plug it in; it does not need to be programmed.

 

RonJ, you're the guy that helped me a lot by linking to the detailed diagnostic flow-chart that I used and that seems to indicate the ECU is messing up. It was P1491 and the passages were completely gunked up in the intake manifold. I didn't get into the head to clean it though. According to the flow chart, it seems like it must be the ECU based on a couple of the tests, I don't remember which, but the EGR valve was sending the right messages and the wires were good in between. So, where can I find an ECU? Don't good ones get swapped out by the high performance enthusiasts? Thanks.

 

My ECU is a 37820 P2N A33. I understand 37820 just means ECU. P2N is the model or something? "A" means US and I guess 33 is something like the version or update. I can find P2Ns online, but what about the last two numbers? Do they have to match or will any of them work without throwing CELs?

 

The a33 part just indicates whether the ECU is for an auto or manual (or CVT). If your ECU is truly bad, then you'll need to search for a P2N computer that matches your transmission type.