Hi people,

I'm was hoping to air my current troubles with my 6DCT450 and see if anyone has experienced my problems or can help guide me before i get the box out... again.

I lost drive and had the dreaded transmission malfunction cel a while back and plugged it in to get the codes P248a (shift fork B stuck)  P248b (shift fork C stuck) and P0949 (adaptive learning not done). After a bit of research it was highly likely the plastic retainers has broken down and gone on their travels around the gearbox.

Gearbox removed and stripped (courtesy of many Russian YouTube videos) there was a stuck valve in the mechatronic and one of the ports in the gasket had been blocked by the plastic. Mechatronic was cleaned out, solenoids tested and cleaned, gearbox stripped, inspected and cleaned, clutch springs and plastic retainers replaced, new sacrificial oil seal. Everything went well and looked acceptable (bear in mind i am in no way an expert)

Gearbox back in, oil filled and it worked.

Over the first few drives it was quite hesitant on shift, shudders from 1st-2nd and generally lumpy in operation but worked and currently still works with no cel lights. Oil has been changed again since the rebuild and then checked level a few drives later

Plugged it in to FORScan and i'm still getting the error code P0949 (adaptive learning not done) which would make sense as i didn't do any learning procedures. I attempted the clutch learn first which went well but it will not do the shift fork learn, it completes the plausibility learn but will not complete the actual learn. So has anyone got any experience on this?

There is also with the above P0949 an error code that is albeit intermittent of P0715 (input shaft speed sensor 'A' circuit) signal erratic. Logic would suggest i need to replace this and this will hopefully solve the shifting issues but i can't see it solving the P0949. I'm just worried that i will remove the box replace the sensor and still end up with the P0949 and possible TCM replacement. Which i could have done without removing the whole box. To add i clear the DTC of P0715 before attempting the shift fork learn.

To add to it all there is a oil leak from the bell housing to engine, it seems slight but it is there. I am guessing either my cheap Chinese clutch seal is leaking or something else? I'm not sure if this could effect anything especially if its getting on to the flywheel and beyond.

There is also a possible oil leak from the cooler to the filter housing but i'm not too worried about that for now.

A bit of a waffle. I will update this post as i go through the solving so that it can hopefully help someone else.

Thanks Jon

(2012 Focus 2.0 TDCI 163)

 

It sounds to me like you have a wiring issue too.

First, remove the earth straps from the body, clear away the paint, grease and refit, they are underneath the air box.

Then you need to get the wiring to the transmission from the TCM checked as you can get internally broken or corroded wires, I believe near the rear of the battery tray, on these.

Check the continuity of every cable from the transmission to the TCM and the TCM to the PCM

Oh and if you have a paid FORScan license, consider updating the firmware in the PCM & TCM, make sure you connect a battery charger and only attempt with the recommended cables

Hi Dave,

 

Thanks for your speedy response.

I will have a look at the wiring i have watched a few YouTube videos of people checking the wiring from the main connector behind the arch lining under the battery. I had to drill out the battery mount due to corrosion which i'm told is a common issue, so corrosion could be likely.

I haven't paid for a full FORScan license but it updating the PCM/TCM was on my list of things to figure out how to do. I will look into the extended license.

I will report back with my findings.

Thanks Jon.

46 minutes ago, aRcAnGeL said:

updating the PCM/TCM was on my list of things to figure out how to do

There's a really good "how to" on the FORScan forum, if you follow that you will have no issues

PCM & TCM are quite safe to update anyway

Just don't attempt it with a cheap Chinese lead

Thanks again.

I had a cheapy elm327 but bought a VLinker recently in case that was the reason it wouldn't adaptive learn.

I managed to get a 2 month extended license free trial as well!

1 hour ago, aRcAnGeL said:

I managed to get a 2 month extended license free trial as well!

That won't allow you to download software and perform firmware updates unfortunately.

You need the paid license

It will allow you to do everything else though, including checking if you have updates available, before you buy a license

So it would seem, I extended the license so I could perform a reflash I think you'd call it. But there were no updates available for TCM the PCM had one but forscan advised me it wasn't compatible so I decided not to update it.

Cleaned all the grounds. Will have little play with the multimeter tomorrow. 

 

Thanks for you advice today Dave, it's appreciated

Thought i had better share how the gearbox issues have developed.

After attempting all of the above to no avail, i made the decision to have the box out again and replace the sensor. This solved the P0715 fault and then enabled me to do the shift fork learn and solved the P0949 fault. Thank you for your help.

You'd think everything sounds good! but no, it unfortunately hasn't solved the shuddering from first to second and it now has a creep sounding creak when initially applying power forward and backward. Other than that the gearbox is functioning correctly.

So i'm going to have a sabbatical for now as it works and is much safer to drive, i will readdress in the new year all being well with i guess a replacement clutch pack.

The possible lesson i have learnt is to replace the sensor, clutch pack, both filters and end seal even if they were not an issue before. As this removing gearboxes on axle stands whilst on your back is not good for health either by the stress or the fact it's a very heavy lump of metal.

I will update if i decide to do the clutch pack...