PCM Switch?
- Thread starter ShadyLS
- Start date
joegr
Dedicated LVC Member
If you had searched, you'd have your answer already.
1. Get PCM of matching configuration. (from same year, same engine, same sport or non-sport, ...)
2. Disconnect battery.
3. Remove old PCM, replace with new (probably used) PCM.
4. Reconnect battery.
5. Tow to dealer. Be sure to take all your keys. If you only have one key, you will have to buy at least one more. (a minimum of two keys is required). Alternately, if you have a really good scan tool, you can marry the PCM to the cluster to your keys yourself. The engine will not start until this is done.
Have you done any real diagnosis of this? There are far more common causes for "shifting" problems than a bad PCM.
1. Get PCM of matching configuration. (from same year, same engine, same sport or non-sport, ...)
2. Disconnect battery.
3. Remove old PCM, replace with new (probably used) PCM.
4. Reconnect battery.
5. Tow to dealer. Be sure to take all your keys. If you only have one key, you will have to buy at least one more. (a minimum of two keys is required). Alternately, if you have a really good scan tool, you can marry the PCM to the cluster to your keys yourself. The engine will not start until this is done.
Have you done any real diagnosis of this? There are far more common causes for "shifting" problems than a bad PCM.
Telco
Dedicated LVC Member
Most common problem with shifting is a bad solenoid pack. My own has this problem. 1-2 shift hits hard, 2-3 kinda kicks back then shifts again. I will report the results on that when the parts get in, then I get a chance to replace.
Are we talking about shifting problems in automatic or Select-Shift?
jjcool00
Dedicated LVC Member
This I wasn't aware of, good to know! Thanks.
BTW, several dealers and independent transmission facilities near me have stated that the 2003-2004 PCM is notorious for causing transmission issues.
I bought a 04 LS somd guy was parting out and i was gonna swap the PCM to see if that changes my shifting problems and if not i was going to swap out the transmissions. It shifts hard from 3-4 on automatic and select-shift.
With a total 2003/2004 production of ~60K vehicles spread out all over the country, I find it hard to believe that a localized independent transmission shop would have that much experience with the LS. The valve body was an issue in some '03s.
Ls_marley01
Active LVC Member
I had that issue,but found out it's a bad shift spring between 3rd and 4th gear , then I get incorrect great ratio in gear 5..code p0795 pressure control solenoid c my car only shifts to 4th if I put it in SST mode
jjcool00
Dedicated LVC Member
I found it hard to believe as well, at first. Until the last 6 months where I visited over 10 dealers, and 10 independent facilities. I even visited with the guy who had been rebuilding specifically 5r55 transmissions who told me he did about 3-4 of these until he realized it was the PCM. He had also done about 12 total within the last two years and had 2 sitting in his lot when I got there because the PCM is on back order. Believe it.
Must be nice..... There is only 1 Lincoln dealer and 6 or 7 Ford dealers in all of San Diego County! The Ford dealer I've used would rather sell a Fusion (yea.... right) to me than properly fix my LS!!!
jjcool00
Dedicated LVC Member
Well I used to live very near New York City, there were about 5 dealers within 10 miles of me alone. I've also visited a couple up here in Mass as well, and have heard the same responses.
Funny you say that, the one dealer I went to up here when I told the "tech" about my car he said "why don't I get a sales guy over here for you and you can look at the MkZ?"
Funny you say that, the one dealer I went to up here when I told the "tech" about my car he said "why don't I get a sales guy over here for you and you can look at the MkZ?"
Pretty much got the same line last time I went to the dealer. They wouldn't even give me an offer on trade in, told me just to sell it myself.
joegr
Dedicated LVC Member
You are also forgetting that 03 was an odd year where some 03s seemed to be something of a mix of gen I and gen II. I, for one, can make no promises of PCM compatibility.
Why are you so certain that this is a (rare) PCM issue instead of a (common) mechanical transmission issue (solenoids, valve body, servo bores, ...)?
Why are you surprised? The only reason I go to Ford dealers is because they still support T-Birds.
@joegr well im really not quite sure. My trans kicks hard when i put it in reverse and always kicks from 3-4 in automatic and SST mode. I recently got my hands on a 04 LS8 thats someone was parting out and i figured i could use it for many different parts because its a gen II. Ive read that a PCM csn cause shifting problems so i was going to try to swap those out to save me the trouble of swapping transmissions. But if they arent compatible then i think that might be my only option.
Classic shift solenoid problem, which can be fixed. You'll probably waste time and money on the PCM.
