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1995-2002 Range Rover P38A
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Discussion Starter #1
I got my shiny new Nanocom yesterday and was excited to see what sort of codes were hiding behind my Gearbox Fault. Unfortunately it is returning no codes. All the documentation I can find implies that I should have codes in the transmission controller and that the Nanocom should be able to read them. Any ides about where I should be looking? I totally am assuming it is a case of operator error on my part. If not is there any idea of what could be the source of this problem.

If the fact that the transmission control box is not retaining the codes is a sign of something wrong with that unit can I just swap it out? There is only at a local "auto recycler" for $75 that I could take a chance on.

Thanks!
 

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I would verify the transmission module is actually activated in your nanocom. There used to be an activation process for BBS products. You scanned your car and sent a series of numbers to BBS who then gave you activation codes. Don;t know if they still do that but that is how they would lock the unit to your VIN.
 

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1995-2002 Range Rover P38A
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Discussion Starter #3
I am able to read data from the transmission so I think I am good on the code. They gave me 2 one for the motor and another for all the other p38 modules.
 

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You only need the codes on the earlier BBS products, the Nanocom isn't VIN locked and will work on any P38. The difference is that a Nano with a licence for a GEMS motor won't connect to the engine on a Thor or diesel but will still work with all the other modules, ABS, Gearbox, EAS, HEVAC, SRS and BeCM.

The gearbox ECU is unique to the P38 and a bit of an oddball. Have you checked through the faults in RAVE to identify what the problem may be? Does the LED next to the gear selector and the dash display show the correct gear?
 

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1995-2002 Range Rover P38A
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I seem to recall your original issue was various low battery voltages, and that lately you have 14.something for the BECM and 12.something else for the engine.....
If you feed the trans a low voltage it will throw an erroneous code which, I believe, will not be logged.
You need to sort out the low voltage before blaming the nano, as the trans is probably fine.....
 

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1995-2002 Range Rover P38A
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31 Posts
Discussion Starter #6
I checked the gear selector and it does match the dash display and and the transmission computer is reporting the same value. My problem is the I cannot fine any fault codes to check in the transmission. I assume the codes are supposed to show up in the transmission module just like the codes show up in the other modules.

Bolt: Thanks, I did not mean to blame the nano. Every reference I found indicated that there should be a code when I got the gear fault. So I have been hung up a bit on that. I am a bit concerned about the voltage at the transmission being to low though since it is reporting 14+-.2, the computer for the engine was the one that was low. But they do communicate so it could b related. I will give it a look in the morning.
 

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Hi ukko I am having the exact same problem with my 1995 P38 4.6
I had my second flex plate shatter on me and after changing it for a heavy duty Ashcroft unit and new crank position sensor I had the same mysterious "Gearbox Fault" flash on the dashboard. If I turn the ACC on it does not appear and then as soon as I crank the starter it flashes on the dashboard and I lose most gearbox functions (Sport Mode etc.) and the vehicle feels like it is in limp mode with very sluggish acceleration, early shifts, very firm shifts etc.
It flashes on the dashboard again when I turn the car off.
I had originally thought it was my gear position switch (XYZ switch) but after replacing it earlier today with a new switch it still has the exact same problem. As you are experiencing I took it to a local Land Rover specialist to read the codes but no fault codes were stored.
I recently purchased a new Optima red top battery which is now very sluggish to start and often needs charging so wondering if this might be an issue? In the past before I replaced the battery I very occasionally had the gearbox fault message appear but if I stopped the car and restarted it the fault would always disappear. Now it is hanging around and driving me crazy.
Apologies for hijacking your thread but very keen to know if you are having the same problems.
 

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In addition to the above I thought I should add that my coolant reservoir was slightly cracked with age and I have been having issues with my temp sensor cycling strangely and rapidly. Obviously there is some wiring under the coolant reservoir which has been getting soaked. I just replaced the reservoir today and will no doubt need to thoroughly clean all terminals etc. to try and rectify the problem. Not sure if it is related and causing some electrical dramas with the gearbox too - let me know if yours is in good shape?
 

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1995-2002 Range Rover P38A
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Discussion Starter #9
Happy day! I got a fault code!

It might be that I was not patient enough on the fault screen for the transmission, it took a bit longer for the cod to appear than I expected. So I would say give the screen a solid 5-10 seconds to fill in the fault code text.

For those interested this is the info on the fault I got from the Land Rover transmission docs:

Fault
Description
CARB
Ambient 1
Ambient 2
Ambient 3
22
Stall speed monitoring
P0722
N_MOT
VGT_$X
MMM
The torque converter has appeared to slip more than the specificed amount.


Diagnostic operates:
Continuously
Conditions to be met to run Diagnostic:
None
Time between fault present & fault stored: 40 ms
Variables used by the diagnostic: Engine Speed, gear selected, Output shaft speed.
Will limp home mode be selected:
Yes
Conditions to be met to clear the fault: Ignition to be switched on whilst fault not present, engine cranked.



 

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1995-2002 Range Rover P38A
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Discussion Starter #10
Updates...

I was not able to reproduce the low voltage that I reported before. Go figure. I will keep my eyes open for that to return.

I have made some progress on the transmission issues resulting in in the gear fault. I have tracked it down to a missing output shaft speed signal. I noticed that I also am also not getting a turbine speed signal, this makes me suspect that there is a connection or wiring harness issue, what are the odds two sensors die at the same time?

So any advice on where I should look for loose connectors? I would like to avoid ripping up too much of the truck following the wires by hand.

Thanks!
 

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There's two connectors between gearbox and the rest of the car under the centre console, at least one of these carries the signal from the output shaft speed sensor.
 
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