P0686 OBD Error Code Help - 2007 Saab 9-3

[Xaan]

I went to go do my smog test to register the car and it failed.

Failed Checks:
OBDII
OBDII Bulb Check

But the guy didn't mention this. He told me that the problem was an P0686 Error code which reads as follows:
P0686 - ECM/PCM Power Relay Control Circuit Low

So far from what I have read online people recommend others to get a new wiring harness, check the main relay and/or get a new/check the ECU.
I spent all my money buying the car and getting it insured. So I can't really afford to do anything expensive.

I just bought a new main relay and in a few days I am going to see if that was the problem(hopefully yes).

I just I'd ask here to see if anyone has encountered this and what they did or any tips really.

The cars starts up and runs fine although a few people with this problem have said that their car accelerates a bit slower which I don't really have a comparison but I guess it could be faster but that could just be the turbo lag.

[Digger]

Spooky, but not the end of the world, happens on Chryslers, Fords and Chevrolets too, most of the time it's a bad or dirty spade lug connection or the relay. The box you need to really look at first is the little box that hangs off the front of the battery box. This thing gets pulled up out of the way to change headlight bulbs and the cable can get strained, so pull it up and look the bottom over to make sure that the all the connectors are up tight into the block and the wires are tight to the connectors. If you find one sticking down farther than the rest, or a wire about ready to pull off, take care of that first.


Not quite as easy to fix is a loose female spade connect inside a 5 pin socket, with the right size sharp pointy thing you can snug these things up while they are still in the socket, finding one that needs to be snugged is easy when it's one of the outside pins by moving the relay front to back and side to side. The center pin can fool you so give that a good close look.

You have a new relay and that's great, if you didn't already have one, scuffing the tarnish of the relay legs also helps the electricity flow through and swapping it for one next to it will move the problem if the relay is the problem. Cheep and effective trouble shooting method.

Wire harnesses do have trouble from time to time and it's usually where they bend and wiggle. So after you've given this relay and connection a good going over, clear your codes, drive the car and if your code doesn't come back call it good and done. If your code does come back clear it and wiggle the cable between the relay box and the motor to see if you can make it happen. Hopefully you won't need to do this or go to the end on the engine controller, those plug ends are made to be tight and you can do a lot of damage if you don't get the things started right when you go to put them back on.

Things like a weak battery can also give you this kind of an error if you have an even slightly tarnished contact, so do get that tested before you go chasing after anything like an expensive part or a lot of little ones.

[Xaan]

Thanks! You really saved my sanity. I'm going to try this after work.