After driving my car, or turning the key to "ON" and then turning it off/removing the key... The commander for my Power FC is still illuminated and displaying information.

When I pop the hood and remove the 30A EGI. COMP fuse, the main relay clicks off and of course the commander is no longer illuminated. Now, where to check and what to do?

 

Hmmm... Perhaps it's similar to my radio issue [same thing, key to off and out, still powered on..]
If I remember correctly, I had to clean one of my grounds.. Driver's side strut tower, the ground with the tab sticking out of the wiring harness down low by the frame rail.

 

I was thinking this may be a ground issue, too.

I've read plenty of other threads about people's cars continually running after being shut off.. But my car actaully shuts off. It's just the ECU (Power FC) seems to still have power and the main relay isn't switching "off".

 

If the Main Relay isn't shutting off you might want to measure for voltage on the B/W wire in the two wire plug. It should have voltage w/key to on, but not in the off position. Another possible scenario is a sticking relay. If the B/W wire has voltage in the key off position then something is backfeeding the Engine fuse. If this were the case it's either occuring at the interior fuse box or the items which the Engine fuse powers.

 

How is the commander getting it's 12 volts?

 

As suggested above..........the commander was wired incorrectly. The power needs to go to a source of switched power. A bad ground will not, cannot cause this problem.

 

The commander is simply plugged in to the Power FC. Which means that the ECU is seeing power after the car is shut off... I still need to check the B/W wire in the two plug connector that satch referred to.

 

If you disconnect the two wire plug and there is still voltage on the Black/Yellow wire and the Black/White wire (or either of them) in the four wire plug then the relay is stuck in the closed position.

 

Okay... When I turn the key to "ON" there is voltage at the B/W wire on the two wire connector, but no voltage when the key is off. When I unplug that two wire connector, turn the key to "ON" (commander illuminates as normal), and then shut it off (the commander turns off like it should.) What does this mean?

 

It appears that it means the two wires in the four wire relay plug that have power w/key to on are not powering the Commander now as they may have previously if the relay was stuck in the closed position. Did you by chance test the B/W wire and the B/Y wire in this four wire relay plug for contant voltage? They should only have power w/key to on. If they had constant power then the relay was stuck at that particular time. I thought you mentioned pulling the COMP fuse turned off the Commander thus the reason it was suggested to look at the relay in the first place. If your Commander is powered by the B/W wire from the four wire relay plug then the relay must have been stuck closed allowing voltage to flow to all items powered by the B/W wire.

 

I only checked the B/W wire in the two wire connector.

 

Checked the four plug connector.
W/L (-- --)B/G
B/W (-- -- )B/Y

B/W and B/Y wires are not getting voltage when key is off. W/L and B/G are seeing voltage with key off.

B/W reads 0V when key is on. B/Y sees about half voltage with key to on. W/L and B/G do not see voltage with key to on.

(When performing these, I have the main relay completely unplugged and out of the bay. Would I still be getting proper readings doing these checks this way?)

 

The relay passes voltage from B/G to B/Y and W/L to B/W w/key to on when everything is plugged in, but B/W and B/Y won't have voltage w/key to on "if" the relay is unplugged, either the two wire plug or the four wire plug or both of them are unplugged. But B/G and W/L must have voltage regardless of the key position and the plugs being unplugged or not for they are constant voltage and are powered respectively by the EGI and COMP fuses.

 

Okay, my bad... B/G and W/L do have voltage with key on and off.

 

That's good because if that were not the case then that would be a can of worms of insurmountable proportions. Then things checked out okay as you tested it.

EDIT: There is a Green check connector w/four wires near the leading coil. If you come across a time where the Commander doesn't turn off as it should then check for voltage on the B/W wire at this Green check connector w/key to off and it should not have voltage. If it does then the relay is stuck in the closed position.

 

Interesting thing happening now... When removing the EGI. COMP fuse, the main relay will no longer switch off (closed?) - (I do not hear that switching noise.)

 

You can tell if the relay were closed or open primarily by whether the B/W and B/Y wire have voltage or not. Closed would mean they do, and open would mean they should not.

 

start backprobing pins at the ECU. Use the FD pinout

 

sounds like a stuck main relay.

 

I feel that the main relay is just sticking closed. It's supposed to open when the car is shut off... Am I not correct?

 

Correct.

 

Lol... Karack must have been a few seconds ahead of me.

Alright. I will probably try another main relay... When I am able to borrow another.

 

Alright. I've confirmed that the relay is sticking closed when the key is off. I opened up the relay, plugged it in, turned the key to "On", visually checked that the relay was closed, turned key off, and noticed the relay was still closed.

Other than a bad relay, what else could possibly be causing this?

 

Nothing if the B/W wire in the two wire plug has no voltage w/key to off which you already confirmed.