About to purchase a GAP IID tool but I just wanted to confirm two things with those that have it:

1. The IID tool can be used to fix the California stop bug by reprogramming the transmission.

2. The fix can be reverted if needed.

 

1) yes but you need to ask gap for that firmware. Otherwise what it does is reset the adaptive values for the tranny

2)yes, but again removing the gap firmware leaves you having to reset the adaptive values. Not a bad thing by itself, but if the tranny hasn't had a new pan/fluid for a while it may shift rough as it has to re-learn shifting patterns starting from a new-factory setting.

This is how it appears to work, someone correct me if I am wrong, I have not yet loaded the CA stop firmware, just reset the adaptive values after pan/filter/fluid service.

 

That is correct. I bought the LR3 transmission firmware update and followed the provided instructions. That was about 15K miles ago and the "CA stop" effect has not come back.

 

Do you like how it shifts now after changing the firmware with GAP?

been meaning to try it

 

Yeah, I never had any real shift problems but at low speed, if I was off then back on the throttle, it would clunk in the drivetrain. The firmware and adaptations flash took care of it. Anyway, I'm not too hard on the car so after resetting adaptations, I drove slow and smooth for a few miles. She shifts and drives great. I never think twice about the driveline now.

 

So when you say you have to ask GAP for the firmware, is there a cost to that? How easy is it?

 

No cost if you own a tool just email them. Going by their other flashes its pretty much have a charged battery and plan on waiting a while while it updates.

 

It was real easy and GAP's customer support has been great. I emailed Patrick (gapteam@gap-diagnostic.com) and explained the situation. He sent me a link and I paid the $38 for the software. He sent me instructions to put the update on the IID tool and then to flash the car's ECU. Step-by-step, real easy.

 

Thanks everyone! Excited to get rid of the jerkiness and clunking in stop and go traffic.

 

Just did the trans fluid/metal pan - no effect
Will do diffs and TC at next service - WITH the GAP tool (need to buy)

New owner here, glad to hear the update "fix" is out there
Thanks forum, for all your info - really helps a LR greenhorn like me!