philipswanson

After rebuilding the engine, my check engine icon light is on but my OBD II scanner shows all clear and no codes. It's a 2007 Mustang. Anybody else experience this condition? I need to get that light out to pass smog but with no code what do you fix?

Thanks, Phil Swanson

tx_zstang

You have to get the code. It might be a body code (starting with "U") or a transmission code, which most readers cant read. Since you just did some major work, I'd suspect a cut/pinched/disconnected wire or connector. My guess is it has an auto trans; if so, mke sure all 5 connectors (2 big, 3 small on top) are still connected, and the smaller of the 3 connectors on the pcm is seated properly in the pcm.

philipswanson

Thanks, I think you are right on. I picked up a new scanner that reads OBD II 3.0. My old one is a 1.0. That did it and I got 10 codes! They are all transmission codes like you stated. Can you elaborate on where these transmission connectors are? You mentioned, "on top", on top of what, the transmission itself?? Yes it is an automatic. Thanks again.


Phil Swanson

philipswanson

Also, it is the V6 4.0 liter with the automatic.

Phil Swanson

Derf00

Have you actually driven it or just cranked it up?

I have't dropped the tranny or swapped the engine but I have done some work inside of the 5r55s tranny you have. There is one plug I am aware of. It's on the drivers side, nearest the bell-housing, on the upper side of the lip where the pan mounts. It's the solenoid pack harness. It is a push fit connector with a 10mm bolt that secures it in the transmission.

By itself it that connector has no fewer than 16 wires that go into it. I'd start there. If it's not seated correctly or not secured with the bolt, it could throw a lot of codes.

It's not easy to access as you have your transhift cable and position sensor harness that sits almost on top of it. You also have your O2 harness that runs in that area. To make matters worse, the bolt is perpendicular to the transmission and sits almost flush so it's hidden from view. I have medium sized hands it was a bear to loosen/tighten the bolt when I worked on that stuff.

philipswanson

Thanks, I will pull that connector out this afternoon and clean it an use some dilectric grease in it and check that harness out where it goes to the PCM as well.

Phil Swanson

philipswanson

We took the plug off the transmission, sprayed out the connector on both ends, plugged it back in and tightened the bolt. All codes went away, check engine light off, O/D off light off and drives like a champ. Much improved performance all around. I sprayed out the connector with 2-26, an electronic cleaner with corrosion preventative mixed in. Leaves a light oil film compatible with all electronics. It can even be used directly on circuit boards and won't cause any problems. Sold at Home Depot, a great product. Made by CRC.
Thanks for all the help guys, it really paid off. Ready for smog test now!

Phil Swanson

Derf00

Nice, glad we were able to help!