Hello!
I am looking for any information regarding a transmission issue- specifically incorrect gear ratio when placing the LR3 in reverse. As the temperatures have dropped, this code and "F" notification has popped up on my 2007 LR3 HSE w/140k miles. I have changed the Transmission fluid, twice with the Atlantic British transmission kit as an FYI. I have had this issue for 6 weeks or so, particularly when its cold out. I clear the Faults and it drives just fine, shifting can be a little bit more "harsh" but not very much. I am not sure if its just cold transmission fluid, dirty transmission fluid or a computer issue.
I searched the forum and the only thing that popped up was gear shifters stuck- mine is not stuck, just places the truck in a safe-mode- where it limits speed etc. The resulting fault triggers the next code U0402-94 Invalid data received from the transmission control module.
Does anyone have any experience with this?
Thank you!!

 

Anything that says invalid data makes me want to start with connectors and wires. First make sure the transmission ECU connectors are clean and free from corrosion, and are seated correctly. Second I would make sure there wires have low resistance between the ECU connectors and the Instrument panel (or even the ODB II socket)
If all that checks out, maybe look at the ECU itself.
And as a check of my work, I would once again check the fluid level of the transmission following the service manual procedure.
I may also consider doing a adaptation reset on the transmission ECU to give it a fresh baseline after the fluid change.

That is all I can think of before my 2nd cupof coffee this morning.

Hope that helps
Jeff

 

That seems pretty good- I have had issues with the ECU and water intrusion in the past. Additionally, have had a couple of deeper water crossings as of late.
All before 2nd cup- impressive!
Thank you!

 

I have to ask, you did fill the transmission with the vehicle running, right? And is the battery good? I remember when I had a dying battery. It would start but I would get the F code, but also ABS would drop out, etc.

 

I don't think the battery is dying- regularly 13.9- 14.1 when running. I need to check when off- I believe its 3y old 935cca AGM battery. I need to check the off voltage. I do have a lot off junk running off the the cigarette lighter ports as well as a winch- (though only run it when the car is running). Will take a look at the off volts--

 

so checked and its 38F degrees out and battery is 12.1v. Tested earlier (2hrs) and just now - still 12.1. Starts fine- but on the low end of voltage. I replaced the Alternator a couple years ago when I swapped the battery. With a lower voltage on start up - would that trigger a Transmission fault?

 

It certainly can cause a fault. But usually you get a couple other odd faults too. Also voltage is not a true reflection of battery health if there is a bad cell or two. A simple test would be to start it with an additional jump pack or battery tender. Something to give extra power on starting.

 

I appreciate the info- will try with a jump starter for the extra juice- and see, But that would make sense, because shutting it off, and turning it on again usually eliminates the issue. The added juice from running the alternator for 1min or so.