2012 Focus SE with DPS6 transmission
Was having issues with random errors being thrown up while driving, like Hill Start assist not working.
Eventually enough errors seemed to confuse the ECM and the car would not start, so would disconnect the battery and then car would start.
Finally car would not start; turn key 10-20 times with no response, then eventually car would start and drive normally.
Mechanic tested lockout switch, ignition switch, battery, grounds and concluded there was a communication error between TCM and ECM.
He installed a startup bypass button so I could turn the key then press button and car started and drove normally, for about a week.
He finally concluded the TCM was faulty.
He installed an aftermarket TCM, performed reprogramming and re-learning and now have all sorts of new issues.
Car starts, but only after a series of relay chattering goes on for about 5 seconds.
Car will go into drive, but computer shows it goes into second gear. It will move forward, but clutch seems to only partially engage.
Same with reverse, which I assume because same clutch is used for reverse, 2, 4, and 6th gears.
Receive clutch position sensor errors (P0805 and P2872)

So...trying to determine next step and could use some guidance.

Bottom line is that the transmission worked fine when communication was correct.
Is it possible that the replacement TCM was not programmed properly?
Is it possible that aftermarket TCMs are not compatible with Ford ECMs?
Do I put the original TCM back in and see what happens?

My head is spinning.
Any guidance wold be appreciated!

 

Unfortunately, most shops don't have access to the info needed, because it requires a subscription that costs $$$.

You may wind up having a dealership straighten out the problem. AND,,, that will cost a few $$ too,

 

Was hoping to go that route as a last resort, because the car has a re-built title and the ones I have spoken with aren't thrilled about working on it.
I'm thinking it might be best to go back to the start and see if errors go away.
If I re-install the original tcm, do I have to go through any re-programming or does it save past settings?

 

Most times when we change modules they need to be programmed to the individual vehicle.

Then when we go to reinstall the original module , the system sometimes gets confused and now nothing works right if at all.

We cannot do with newer vehicles what we were able to do years ago. The better thing is to have a shop that is equipped to do all this and have it done right, once.

Some shop are equipped and most are not. There is a lot more to repairs these days than a few years back and it is getting more complicated and demanding .

Security systems get into the picture and now only a dealership or certified locksmith can reprogram those systems. Not too many alternatives.

 

Understood.
Just frustrating.

Thanks!