Hi all,

I have swapped over the Trasmission Conrtol Module on my Freelander and it spits out F4 error code otherwise drives fine. Do these boxes require programmingf? If so how can this be acheived?

Thanks,

Musa.

Raises some questions !
Why did you change it?
What was original fault ?
Did you have F4 before the change?

No coding needed but need the right one for the engine. TD4 or V6 etc..

Hi Andy,
Thanks for the reply.
Original fault was 4th gear slipping when warmed up ( does not do it when cold). My first thoughts were solenoids because of 3rd gear changing erratically when warm. İ replaced all solenoids with no success
Next was a possible crack in reverse piston as was mentioned in another post. Had the same symptoms as a cracked piston. This was checked and found no problem within the transmission.

İ then tried swapping the TCM from another TD4 this was from a facelift model. This fixed the original fault (slipping 4th gear and erratic change of 3rd gear) but when ignition turned on comes up with F4 error - this only happens on Park and Neutral positions.
The car otherwise has no issues. So my thoughts were either my TCM is faulty and have another fault elsewhere or unit does not match the same specs. Also want to note that when in park position it shows N on display not P as it should. Other positions are fine.

First pic is the original TCM second is the swapped over one.

Thanks

Musa

PS only had F4 occasionally when gear shifts were harsh before the change.

I detailed the reverse clutch change on a pre 2000 model. Yours should have the modified piston already.

My (limited) experience with Jatco boxes is that an F4 and any slip are mechanical rather than electrical problems. I am surprised a change of ecu sorted the slipping.

@Nodge68 had the F4 problem but don't think he bottomed it completely.

Sounds like maybe 2 faults. Be worth reinstating the old ecu and see what comes back?

i dont think they changed the ecu significantly with facelift.

Need to research F4, I think it is when the gearbox is not happy and puts it into 4th gear to get you home ??

Courtesy of @Nodge68



F4 means the gearbox TCM (Transmission Control Module) has implemented its limited operating strategy (commonly called limp mode). This means the gearbox will be locked in 4th gear only (reverse is normally still available). The only way to find the cause, is to have the TCM codes read, by someone with a suitable code reader.

Maybe your ecu connectors need cleaning for the F4 ?? Or a broken wire when changing the unit.

Hi Andy and thanks for your reply.

İ have checked connectors and all seems fine. İ did notice a bent pin on the original ECU checked it and it was earth. Straightened it and no change. My issue is possibly more electronic than mechanical as the internals of the jatco have been checked the valve body was also replaced.
With the original ECU F4 would only occur when 4th gear had slipped and then jolted in . But with the replacement ECU all gears are smooth with no issues but spits out F4 as soon as i turn on ignition. This was what lead me to believe some program issue. As you stated i could have two fautls. İ need to further investigate.

Also to note with the original ECU it seems like there are two gears in fourth gear. When it goes into fourth the revs click down twice. This doesnt happen with the replacement ECU.

Thanks

Musa
.

Have read codes but to no avail. Results attached.