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Premium Member
1970-1995 Range Rover Classic
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425 Posts
Discussion Starter #1
Well I am really sorry to bother you again.. i sincerely hope this is the last I am posting about the P38 from hell.
(just for my own sanity, I have restarted and repaired 5 others in the meantime and all went fine, this one is the worst ever) FYO it is an italian market Diesel Manual late 1996.

have tried every which way to push the button and get it back out of low, tried neutral with the fuse, worked, but won't go into high.

what I have done so far..
checked ALL fuses
checked continuity form fuse 4 to supply, to the back of the BECM where the cable leaves to the transfer ECU

checked continuity form fuse 4 to pins 23/24 on transfer ECU
checked presence of 12 V

Yes to all

Borrowed another transfer ECU, an earlier one from an auto box v8.

the same thing.

(Put the other one back into its place before boss shoots me..)

it also tells me fuse 22 is bad, but all windows and doors work fine.

Dunno where else to look at the moment, I have been back and forth through the wiring diagram and can't find anything alse connected to either fuse.
 

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SUPER MODERATOR
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27,723 Posts
I would check the motor first. They have a habit of freezing up if not used on a regular basis.

Does the dash button light up when you push it? If it does. I am not sure were where the trigger wire goes because we do not have manuals in the NAS market.
 

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Premium Member
1970-1995 Range Rover Classic
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425 Posts
Discussion Starter #5
thank you the light stays on as it should, telling me it is in low. the weird thing is it doesn't blink as it should when trying to get into high.
ToadHall I thought you were in WA..had see that but i must have been dreaming.
 

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SUPER MODERATOR
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27,723 Posts
I am in WA... Warshington. ;-) I haven't made it the WA down under.

Any way, if the auto ECU is interchangeable, just using different inputs, and you have continuity I am a complete loss. It's odd that fuse 4 is reading as blown. Among all your expertise have you ever pulled a power board out of a BeCM? You might check for obvious cracks in traces or look at the fuse four connection on the fuse holder. It's stretch....
 

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Premium Member
1970-1995 Range Rover Classic
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425 Posts
Discussion Starter #7
well i am just having a bite to eat then i will check what happens if I spin the motor.

Expertise ..hm today I am having doubts about myself
Sure yes I have been thinking of the BECM myself. had it open only 3 weeks ago. But it seemed OK. Have to find out why the heck it thinks in a line of continuity there is a blown fuse.

WA.. have been working ( not very legally) in Tom Price and even weirder places many years ago. Been in Kintore ad God knows where.
Of the US I don't remember much, that was in 86 and best forgotten. Found a great job but mentality was too tricky for me. I don't like guns you know, even less in my face.

Well somebody thinks a lot of my knowledge because I have been offered a job in SP. 7000 Mil Reis a month. Guess I am moving again, really looking forward to the idea of being able to buy a transistor or a plug if I need one. or even a decent soldering iron. Just hope my braain does not fail me
 

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Premium Member
1970-1995 Range Rover Classic
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425 Posts
Discussion Starter #9
yes, been down to grease.
The boss has been spinning the motor back and forth underneath. We jacked two wheels up and I put it in gear, measured the switches at the ECU end of the cable etc. After 3 attempts I could already feel in the clutch when it engaged 1st in low or in high. We watched the wheels spinning and decided we know how to put it. reading the switches is less obvious, it kind of always stops in a nonexisting or 'Zone' or end position, impossible to get a fine tune to high.

So engaging it into 'left of hi' 1010 was the best we could achieve.

Now here is what beats me.
it still has the little light on on the dash but ¡not! the L in the instrument panel info line.
it also insist that fuses 4 and 22 are bad.
WTH

i gotta to get this sorted somehow but.. :x:confused: i am still puzzled. I want this job in SP so I gotta finish up all trouble

so we know it is not the motor. the cable seems to be ok cause I can read the switch positions.
 

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Registered
1995-2002 Range Rover P38A
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107 Posts
”An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system.”

I like this word since it’s neutral and doesn’t refer to any specific type of actuator mechanism.

Anyway, have you checked the voltage to the motor while changing between the modes?
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
As far as I know the Manual and Auto transfer case ECU's are different - I've got a couple sitting on the shelf and the manual one has a different part number and different coloured sticker on it... So putting an Auto one in might not make a lot of difference if it's expecting a different input.

The transfer case ECU gets it's power from Fuse F4 (30A) which I think is the main supply for the range change motor. It also has another supply from Fuse F6 (10A) which I believe is the power for the actual ECU.
The power from F4 appears at the transfer case ECU on pins 23 and 24 (purple wires) so that would be an easy one to check and make sure power is getting out of the BECM and to the ECU. This is permanently powered.
The power from F6 appears at the transfer case ECU on pin 4 (Manual transmission - this is Pin 21 on an auto transmission vehicle). This is switched ignition feed, when ignition is position II or III

The transfer case ECU gets connection to ground on pins 5 and 29.

The transfer case communicates to the BECM over 3 wires - which are a direct connection - no other connectors in the loom, but these could also be worth checking for continuity in case one has a break in it.

The connection from the dash switch (on a manual vehicle) and the BECM and transfer case ECU (to detect when range change button has been pressed) goes through a 4 way connector - which RAVE handily doesn't have a photo location for... but my guess would be RH footwell behind the kick panel, as 2 of the wires go to the BECM (for the lamp backlight and telltale) and another wire is the ground for the lamps/switch (which goes to the BECM ground point behind the BECM) and the last wire then goes to the transfer case ECU.

That wire should be fairly easy to check, as the switch wire turns up at the transfer case ECU on pin 33 (same for auto/manual vehicles). A continuity test between that pin and ground will tell if the switch signal is getting through. If you get a connection to ground when the switch is pressed in for low range, and open circuit when released for high range, then it's working OK.

It could also be worth checking the neutral select switch (on pin 34 of transfer case ECU - Manual only) - again should have connection to ground when in neutral. This is probably OK as if vehicle doesn't think it's in neutral, then you'd get SELECT NEUTRAL on the dash if you try to change range I think.

There are some other things to check like the encoder switches in the transfer case ratio motor - as there's a truth table as to what should have a connection to ground depending on motor position, but from what you've described it probably isn't getting that far.. Also there's a couple of buried connectors which the transfer motor and encoder switches go through between the ECU and the motor itself, which I've heard of causing issues in the past - but I think it's worth checking out the input side first.

The miscellaneous fuse failure messages could be issues with a bit of corrosion on the power board of the BECM - or something along those lines - F22 is the power for the front door outstations... given how you said the wiring on this vehicle has been messed with - who knows what has happened! But worst case, swapping the power board should sort that.

Hope this helps.

Marty
 

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Premium Member
1970-1995 Range Rover Classic
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425 Posts
Discussion Starter #12
As far as I know the Manual and Auto transfer case ECU's are different - I've got a couple sitting on the shelf and the manual one has a different part number and different coloured sticker on it... So putting an Auto one in might not make a lot of difference if it's expecting a different input.The transfer case ECU gets it's power from Fuse F4 (30A) which I think is the main supply for the range change motor. It also has another supply from Fuse F6 (10A) which I believe is the power for the actual ECU.The power from F4 appears at the transfer case ECU on pins 23 and 24 (purple wires) so that would be an easy one to check and make sure power is getting out of the BECM and to the ECU. This is permanently powered.The power from F6 appears at the transfer case ECU on pin 4 (Manual transmission - this is Pin 21 on an auto transmission vehicle). This is switched ignition feed, when ignition is position II or III
this explains why the other ECU brought no joy at all. Unfortunately there is no tother manual one I know of .The f4 supply is quadruple checked and fine.The transfer case communicates to the BECM over 3 wires - which are a direct connection - no other connectors in the loom, but these could also be worth checking for continuity in case one has a break in it.
The connection from the dash switch (on a manual vehicle) and the BECM and transfer case ECU (to detect when range change button has been pressed) goes through a 4 way connector - which RAVE handily doesn't have a photo location for... but my guess would be RH footwell behind the kick panel, as 2 of the wires go to the BECM (for the lamp backlight and telltale) and another wire is the ground for the lamps/switch (which goes to the BECM ground point behind the BECM) and the last wire then goes to the transfer case ECU.
I have found that one, here it is a bit lower than the back of the HEVAC.
That wire should be fairly easy to check, as the switch wire turns up at the transfer case ECU on pin 33 (same for auto/manual vehicles). A continuity test between that pin and ground will tell if the switch signal is getting through. If you get a connection to ground when the switch is pressed in for low range, and open circuit when released for high range, then it's working OK.
sorry it only says 'change range', not High or low. For some bizarre reasons, it is the BECM that sets the light on or off.But yes, I will check the BECM connection, there is no reason the button stays in low if it is not the case.
It could also be worth checking the neutral select switch (on pin 34 of transfer case ECU - Manual only) - again should have connection to ground when in neutral. This is probably OK as if vehicle doesn't think it's in neutral, then you'd get SELECT NEUTRAL on the dash if you try to change range I think.
Neutral works fine, I tested that with fuse 11 and receive no cheeky comments from the message center
The miscellaneous fuse failure messages could be issues with a bit of corrosion on the power board of the BECM - or something along those lines - F22 is the power for the front door outstations... given how you said the wiring on this vehicle has been messed with - who knows what has happened! But worst case, swapping the power board should sort that.Hope this helps.Marty
Sure you always help. If your ship ever docks in central America let me know so that I can pay you some beers. Or a decent meal.I can already see myself reefing the BECM out again.
 

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Premium Member
1970-1995 Range Rover Classic
Joined
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425 Posts
Discussion Starter #13
update.. f6 and pin 4 and the 2 earths are fine. pins 14, 35 and 36 seem to be part of the problem 14 - 0,2V means low 35- 12V means not in neutral 36 - 12V means not in high. but it is in high! my motor switches tell me it is in zone 1 now.. well it definitely is in high
 

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Premium Member
1970-1995 Range Rover Classic
Joined
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425 Posts
Discussion Starter #14
Well here is the solution.
As the light on the button depends on the BECM and there was a wrong information floating in the system it meant the BECM had to come out again . The fuse xx is blown status seems to be checked by this block and in case of number 22 it is a big more tricky, on the side in the 3rd photo.
As you can see, n°2 which is for fuse 4 should have 5600 ohm. Turned out to be 158k ohm, which then probably sets the status to blown

Morale.. next time I get a mystery fuse message, I will go hunting for my resistor bags first.


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LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
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4,159 Posts
Sorry, work got in the way with me being on the forums the last few days...Did that sort the transfer case not working too?Also, the neutral switch I was mentioning is from the gearbox neutral - not the transfer case neutral.12V on the wire for the low range switch does mean high range - is should be connection to ground when the switch is pressed in.Glad the BECM fuse failure is sorted too - they usually are silly things like faulty resistors (found one like that for a lamp error message) - but they just take a bit of time to trace!
 

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Premium Member
1970-1995 Range Rover Classic
Joined
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425 Posts
Discussion Starter #16
Sorry, work got in the way with me being on the forums the last few days...Did that sort the transfer case not working too?Also, the neutral switch I was mentioning is from the gearbox neutral - not the transfer case neutral.12V on the wire for the low range switch does mean high range - is should be connection to ground when the switch is pressed in.Glad the BECM fuse failure is sorted too - they usually are silly things like faulty resistors (found one like that for a lamp error message) - but they just take a bit of time to trace!
Thanks Marty,
I thought it was the clutch switch that allows the shift.. As I remember from my p38 you could happily shift in 1st or 2nd from low to high doing under 15km /h .. makes perfect sense if you are towing another p38 on a trailer. I also used to do it on the VM 2 door classic which has a Borg Warner without the hassle.
But you are right it is there. You live and learn.. something to check on Monday.

We should put our heads together and make a BECM false message list about power board findings

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