Hi Peoples

I've read that a reflash of the TCU may cure my 3 to 4 violent shifts. (the common fault where the engine revs then slams into gear) I know how to clear adaptations with my Gap tool, but what is a reflash? A Jaguar site describes disconnecting the -ve battery terminal and touching it to the +ve terminal for 10 seconds.

And, I've read here that after clearing adaptations, one does not have to do the complex relearning exercise from BMW. Just drive normally and the TCU will relearn.

What to do.....

Thanks!!!

 

I’m guessing reflash is update the firmware microcode to the TCM.

Not sure how that clears anything. One would assume that the firmware is not stored on the same media as where ever the settings/parameters are stored. Nor would one assume that the whole firmware image would write over the settings. I mean, embedded design wise it sounds a bit silly.

 

I did find some information. Reflashing is indeed uploading updated files to an ECM. Gap can assist by emailing your ECM summary to them and they send you recommended files to upload. It looks to be chargeable but not expensive. Will get on this and post a step by step summary. Merely deleting the adaptations may not be enough. We'll see...

Rob

 

You only need to reset adaptions if you change any internal hardware like solenoids etc, it wont cure shifting issues.
I'd say you'll need more than a reflash and likely some internal repairs.

 

There is no situation where hard shifts are normal and there is no situation where adaptations will cause them directly. You need to service the transmission. You may have a failing solenoid but a proper diagnosis is in order.

 

Some background. I bought the car with the transmission not working and the car not mobile (for very little).

When it was delivered I started the transmission service. I had new ZF solenoids, new ZF fluid, new two piece oil pan and mechtronic -to-transmission seals.

First thing I noticed was that the transmission only drained about 2 liters, there was oil everywhere and the fill plug was finger tight. I did the service, filled correctly and deleted adaptations. Car drove fine except that 3-4 shift. If I am light on the throttle it will shift fine. Just at a certain rate of acceleration and just at 30MPH/50KPH it will do the rev-slam.

 

You could try fitting a sonnax zip kit, a guy on the disco3 UK forum had similar 3-4 shift issues after a rebuild and turned out to be the torque converter.