RangeRovers.net Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
Hi everybody.
I just bought a p38 4.6 HSE. I've had a long time ago a p38 2.5 DSE that was always in maintenance, very expensive. I love HSE so i decided to buy this one thinking i would work on it whenever possible.
But my first very problem is the usual one: GEARBOX FAULT as soon as I turn the key, the autogearbox message appears, limp mode in 3rd gear, no gear indications on the instrument pack, all red leds of gear lever position work.
Already changed the battery, but the very strange thing is that several technicians have tried to connect diagnostic tools to retrieve error codes and none of them as able to read the ECU from the gearbox, even 2 of them with the T4 testbook from Land Rover.
Chuiffff chuiffff i am kind of desperate.... Any help.

Thanks.
 

·
Administrator
Joined
·
27,818 Posts
If you are unable to communicate with the ECU it;s time to start cleaning connectors. Start at the OBDII plug as well as checking it's fuse. Beyond that there is the usual voltage issues or possibly a duff output sensor.
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
270 Posts
I'm almost sure there is a fuse for the OBD 2 plug. Be sure to check that. T4 should most definitely hook up. As far as the gearbox goes, that can be a multitude of things. Get the T4 reading first before you spend money troubleshooting.
 

·
Registered
Joined
·
9 Posts
Thanks guys.
I think it's not a fuse problem because they were able to read engine parameters and ECU, and all other stuff, the only thing they were unable to read was gearbox ECU. Is it possible that the gearbox ECU is faulty?? It's a bit frustrating to have all equipment to fix whaterever problem it is but not beeing able to read it, and thus knowing what to fix. One of the tecnicians said it might be faulty connections, i will dismantle and check it wire by wire.
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
478 Posts
The gearbox ECU could just have a bad ground. Go over the wiring schematics in the RAVE.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
Hello again.
New developments in my saga. I tapped the ECU of the gearbox with a screw driver, now when i get the gearbox in D it shows me the red leds of 3rd gear, in 3rd gear its 3rd gear, 2nd gear the led its in 2nd gear, LOL when i engage 1st gear it keeps showing 2nd gear.
Now the funny part, i inserted new ECU and the red leds are all correct showing the right gear, but still have a message of GEARBOX FAULT, but most important its: I was inside the car, dark night, i removed the key and locked the doors, and for my surprise the red led of park was still indicating red, very faint red, i switched in between gears and all the reds of corresponding gear showed the correct indication. what the hell.....
Some of the mechanics i went told me it could be a gearbox problem, but i am thinking more of an electrical problem.
????
Thanks.
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,220 Posts
If the light beside the shifter is staying on, then that indicates the BECM is not going to sleep.

GEARBOX FAULT is one of the first signs of lack of power from the battery - so I think it would be worth running through the electrical stickie at the top of the forum page, to see if you have a charging/power issue.

Even with a new battery, a non-sleeping BECM will still flatten it in a couple of days.

The diagnostic lines for the autobox go through the BECM - so it is also possible that there is a problem inside the BECM which is causing the diagnostic tools to not be able to connect through to the autobox ECU.

If I were in your position, I would pull the BECM out and have a look inside it to see what state it is in. It might also be worth sending it to someone like CallRova here in the UK as they can apparently repair BECMs, or at worst, clone your old settings onto a replacement BECM - if any damage is found.

Might cost a little bit to do, but it will save the headaches later!

Do the electrical stickie first, as it's easy and free... make sure you have a fully charged battery first though. It could be as simple as a couple of bad grounds.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #10
Thanks everyone.
I will start checking all connections, earths and wiring as well as battery and XYZ connections, batterry is brand new, it was one of the first things i've changed when i got the problem, after that will do try to see if it's a problem with BeCM, last thing will be taking the gearbox out and check the sollenoids. If all of that doesn't work, i will tear it apart and sell the car in pieces.
Just one other question that i have in doubt, once i encouter the problem is it necessary to reset the fault in order for it not to appear??? does it need a reset or if i fix it it will work again???
Thanks again everyone, u are always helpfull.
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
478 Posts
That depends. Most of the time it'll go away the next ignition cycle, but if it's a hard fault it could be there for 5-10 cycles.

I could clear my gearbox faults using Torque, so any generic OBD scanner should be able to.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #12
Hi again everybody.
First of all, thanks for all advices given. Although they weren't needed, thank god.
I was suffering from a problem, that probably no one has ever experienced (usual stuff for me).
As strange as it sounds, the problem was the connector plug that connects the gearbox ECU to the BeCM, it's was connected upside down, i dont even know how it was possible for someone connect it that way, without feeling it was wrong, or even how it's possible to connect it upside down. Uffffffff this one was easy to solve, calmly waiting for the next one.
Cheers to u all.
 

·
Premium Member
1995-2002 Range Rover P38A
Joined
·
626 Posts
Hi again everybody.
First of all, thanks for all advices given. Although they weren't needed, thank god.
I was suffering from a problem, that probably no one has ever experienced (usual stuff for me).
As strange as it sounds, the problem was the connector plug that connects the gearbox ECU to the BeCM, it's was connected upside down, i dont even know how it was possible for someone connect it that way, without feeling it was wrong, or even how it's possible to connect it upside down. Uffffffff this one was easy to solve, calmly waiting for the next one.
Cheers to u all.
It was connected upside down? Did it function and drive for a while connected like this or how did you figure this out? Do you by any chance have a picture of this connector as I'm having gearbox fault issues right now that are definitely testing my patience.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #15
Hi there.
Yep it was connected upside down, the car drove "fine" in limp mode, actually the previous owner drove it a couple of thousand miles, in limp mode, without even noticing it, he was a very dumb guy that i can garantee, but good for me this way the car was very cheap beacause it had a problem. LoLoL. Dont know how someone could have done that, it is also strange that the connector is able to connect upside down.
Thanks to that i became an gearbox electric "specialist", i read all manuals, the electric troubleshooting, and so on and son on. I found that it was wrong when i was going to start my troubleshooting. I dont have a picture of it.
But what seems to be your problem???
My message was only GEARBOX FAULT on the instrument pack, as soon as i turn the key on or when i turn the car off.
Everyone here was very helpfull, and there are a lots of threads here that u can read.
I am very happy now, maybe my gearbox is a bit damaged or the clutch pretty used cause always driving in 3rd, but for now drives smoothly no harsh engagements, like new.

Thanks
 

·
Premium Member
1995-2002 Range Rover P38A
Joined
·
626 Posts
Have you a pic of the connector? I may have put it in upside down too a few month back when I got my BeCM back from Scotty (although that would be too good to be true).
 

·
Registered
Joined
·
9 Posts
Discussion Starter #18
Hi again.
If it's a problem with the connection to the Gearbox ECU it's not an intermittent fault, it's always there as mine was, dont have pictures but but i can tell u that it was the connecto of the ECU below left seat, it was plugged upside down, so the faul was always present.
Is that your case or the Fault comes anda goes?
 
1 - 18 of 18 Posts
Top