2004 Mustang GT - No start - ECM replacement
 

I have a 2004 GT, 35k miles with 5 speed manual trans that won't start. It will turn over.

The shop is telling me that they can't communicate with the computer and that it needs to be replaced and it will need to be programmed by a dealer. They are trying to find me a used unit.

I've been doing some research on what could have caused this. I think I read somewhere that there was some type of leak that would short the ECM. Does anyone know if that's true, and if so, what leak? Also, where can I find the part number for the ECM for a manual trans mustang?

Could this be PATS related without the ECM being bad?

I find it difficult to trust shops these days after so many issues with them.

Any insight into this situation or what I should expect would be greatly appreciated!

I don't recall issues with a leak in those years, but in the 05 and up I do. Think it was a drainage hole in the cowl area that would get blocked and run into the passenger side foot well kick panel area where the ecm was, not 100 percent though.

PATS would have been my first thought, but there are guys on here with a wealth of knowledge I don't have.

My first question would be does it have fuel at the injectors and does it have spark.

BTW, a 35k mile 04 is impressive. Exactly the kind of cars I've always looked for when buying.

@GuitarGuy777

The Number For the PCM Should Be on Original Part it Should Be Similar to 1R3T-12A650-A1A In Format. If You Don't Have it Send Me Your Vin to clevparts@aol.com and I Should Be Able to Supply Oem ID# & Part Number. LMK in Forum if You Send It.

If Your Shop Can't Program a PCM & PATS Keys Might as Well Put the Car in a Shop That can. The Pcm Will Need to Be in the car to Reprogram. The Aftermarket Does Supply Reman PCM'S and With that ID# It Should Not Be That Difficult to Locate One. Can't Tell for Sure Though Without the Number. I would be Happy to provide the Listings if they are Out there.

I Have Included a PATS Info PDF. Maybe Helpful, See Second to Last Paragraph.

KC

Thanks for the response. All I know is that the shop told me it was the ECM but I will ask if they checked fuel and spark.

Yeah i thought it was impressive too. I just bought it for $2,500. It sat for 3 years after it wouldn't start. The owner bought a newer boss mustang and basically didn't touch this one until I asked if he'd sell. When he told me he bought it new and had only driven it 35k miles I couldn't believe it. Interior is perfect, but the exterior was dirty as hell from sitting outside for so long unused. Hoping I just need to replace the ecm and reprogram, drain the old gas, put new tires on it, clean up the exterior and redo the bumpers where the clear coat is peeling. I'm thinking I got a helluva deal but won't know for sure until it's back on the road.

Thanks very much for your time. I talked to shop again and they verified that they can't communicate with the ECM at all and said that PATS only disables spark so they should be able to communicate with ECM if it was a PATS issue. They located a used ECM for me and said that the total for the ECM and reprogram will be about $425. I can handle that!

Thank again for your info and response!

I'll update the thread with the resolution when it's all done.

Sounds Fair Enough and The Car Was a Steal!

Best Regards,

KC

I'm thinking so too! Looking forward to driving it. I think I may get in to autocross with it.

Some Pics of the Car would Be Great if You Have Them!

KC

It's still in the shop unfortunately. The shop replaced the computer but couldn't get it programmed so took it to the dealership and it turned out there was some other failed module under the fender that had shorted the original ECM and they had to order the part. Still waiting for a resolution and it's getting more expensive every day. lol . I figured it could take a couple grand to get it up and running so hopefully it won't be any more than that. I'll update with pics once she's on the road!

Yes indeed you are correct, it was the CCRM :/ . The shop told me that it caused the ECM to short... whether or not that's true or just that the ECM could not be communicated with because of the failed CCRM I don't know. After getting it running the fuel pump would shut off after about 15 minutes so they had to replace that too. Ended up costing me $2100 when it was all said and done. The joys of buying a vehicle that hasn't started or moved in several years...

Now that it runs and drives I'm going to have to sort out the fact that the AC isn't working and the brake calipers are sticky. With 36k miles on it I should be pretty squared away after dealing with those issues.

I'm with you Kevin. If it's been sitting that long and I didn't know the car personally, I'd probably change the coolant and trans fluid and filter too if it's an auto. I probably wouldn't mess with the rear end dope, just make sure it's full. Probably do the same with man trans fluid.

I did get an oil change, and I'll look into the brake flush as well. Thanks for your input, I'm definitely looking forward to enjoying it!

Thanks for that, I didn't think about the coolant. It is a manual transmission so I do need to check the fluid.

More great suggstions, thank you! I actually put some Techron additive in it as soon as I filled the tank.
And yes it is currently all original though I do want to add racing stripes and the stripes along the bottom of the sides. The thought of keeping it all original is compelling though.

Thanks for everything I'll try to get some pics posted soon!