Car got plugged into one of those code readers the other day due to some strange engine problem (seems electrical) and came back with an ECM Relay problem so I ordered one along with a doorlock actuator that we needed ($20). Figured it's just a relay so I can switch that out easily...right? Well...I can't find where the ECM relay is actually at to change. Anyone know where it's at? I was thinking it would be somewhere in the engine but it's not in the fuse/relay box.

 

The PGM-FI Main Relay 1 (which powers up the PCM, among many other circuits) is in the underdash fusebox. It's the middle one in the top row of relays.

 

You mean the fuse box that's just above the hood popper? Checked in there...there's nothing but fuses. Is there another fuse/relay box somewhere under the dash that I'm missing?

 

^^
poltergeist said "underdash fusebox".

 

Hmmmm...then the question really is where's the underdash fusebox? How do I get to it?

 

driver's side kick panel probably.

 

If that's the compartment that slides out with all of the fuses inside then there's nothing but fuses there...it must be somewhere else...a box that's not documented in the owner's manual.

 

there's more than just fuses down behind that kick panel.

if you had a service manual or an ETM, you would have all the
diagrams and information that you would need.

 

MM's correct, you'll likely have to remove the kick panel for access, but there are 6-7 relays plugged into the fusebox. BTW, what code was stored, and did you actually diagnose that the relay has failed? (I'd guess you didn't test it if you haven't found it).

 

Nope...haven't tested it. Figured since it wasn't expensive I'd just buy it and replace it.

I'll take the kickpanel out and take a look. Thanks guys.

 

i would real like to know the code if you have it.

 

the code for my acura tsx 04 is P0685 i will like to know is that the relay or its something major. The car runs fine it just turns off wherever but it will turn back one

 

 

Did you get this fixed? please let me know. I have the same issue on a 2005 acura TL, it was overheating because the fans would not turn on. Now it shuts off while driving and has a hard time starting most of the time now. Below is what has been done so far.


It seems the dealership fixed the fan issue, but they weren't able to fix the car shutting off issue. It shuts off while driving.
I tried changing the fuel pump relay. The fuel pump relay that has recall. I want to know what to do before I spend money on a new fuel pump or on the E. C. U./. E. C. M. main F1 Relay. From the diagram on the bottom of the plastic cap the blue relay I had switched is the fuel pump relay, the brown relay is the ECU relay and that's the code I get p0685. The dealership changed the ignition switch and charged me for that. Set the problem was fixed. However, it was not. It took five days for them to look at the car. It's 6 days for them to quote Unquote, fix it. But it was not fixed. It was a Honda dealership, but the Acura dealership is further in my car. Keeps shutting off, so it's not safe to drive that far. It seems to shut off after being on for about. 40 seconds to a little under two minutes.. The battery test fine. I charged it and in the past autozone charged it when I test it. It's at 12.3 to 12.4 volts. without the car running. there is this Type of wire assembly that hangs on the crossbar. the the big metal bar that goes from your struts on top. of your wheels in the back near the firewall of the engine bay. It seems I had forgot but to screw back on and it was just dangling back there and it must have been back there when the car overheated. Does anyone know what that thing does? It goes to the fuse box and the engine bay..

 

It's on top of them fuses in car