Was taking voltage readings from MAF and now car won't start.

[misterman]

First, let me say I am a nwebie and can't find where to update my profile to add vehicle stuff etc. so I apologize for that. I drive a 2003 qx4.

I was taking voltage readings from the MAF because I was looking to install an overide but I didn't do anything other than try to take readings. I did this to all terminals on the MAF while car was off but didn't get any readings so then i put the key in ignition and tried to get a reading from any of the terminals but nothing. Then I turned the key to the on position and tried to take readings but nothing then either so I thought I'd have to turn the car on. I went to turn the car on and it turns over but won't start. I had driven it earlier that morning and it drove perfect. I unplugged the MAF to see if I F'd that up but still nothing. When the key is in the one position, i can hear a hmming noise from the under the hood near the passenger side firewall but don't know if that means anything.

What I was installing the overide for isn't of importance cause I never got to doing anything else.

So, I started reading some posts and it sounds like it could be the ECU. Anyone know where that is located on a 2003 qx4 so I can check error codes... or eventually maybe replace it?

Anyone else had this problem exactly or do you pro's know if my inclination is correct or if it could be something else? Or how I can find a way to determine if it is broken?

Any help is obviously appreciated.

thanks in advance for a quick reply.

[maxnix]

Override on the MAF?

If you put 12V where the ECU expects no more than 5.5V, you might have fried it.

[misterman]

Can't see how i could have done that. I put the neg on the body and the pos on the terminal... is it possible to deliver volts that way?

[misterman]

Ok. so misterman is not the man. He is a dumb A$$. It was the ECCS fuse. Not sure how i blew it but I did. Changed it and my car starts! Wahoo!!! no need for a $400 part!

I gotta say though... I thought I'd get a little more support from this forum. I know I'm a dum$hit but still... like I asked where the ECU was located and although I now think I know where it is because of the FSM I'm still not 100% sure because the FSM is for a 1998 QX4... You'd think someone would at least say "hey! Dumb$hit! it's placed in x location and this is how you get to it. Good Luck moron!"... you know... or something to that effect.

Now i want to get back to my original mod but don't want to take readings for the MAF wires.

If someone would be so kind as to tell me which is the 12v and which is the signal wire and what the other two are for... I'd really appreciate it. My wires are w/b - Black/pink - pink black - orange. see picture

thanks

[qship96]

QX4 owners are few in number around here.....you will get more exposure and answers in the Pathfinder forums, which is very similar to your vehicle{exact same motor/transmission}