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1995-2002 Range Rover P38A
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Discussion Starter #1
97 RR Gems engine.
Engaged low range in Moab to do a couple of trails, when it came to engage high range, transfer box stuck in low range, select neutral message. checked fuses for BECM 4 and 6 no problem
i removed transfer case ratio motor, and rotated shaft on transfer case to the right to engage high range, made the drive to Leadville, but would really like help in getting this fixed for tomorrows trails.
Transfer case motor does not seem to move when removed from case but plugged in, select neutral message, about to take motor apart, i will have access to test book in a couple of hours.
Silver King inn car park leadville

Any help appreciated
 

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When this has happened to me, going back and forth on the neutral t FINALLy engaged high range.
 

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Discussion Starter #3
Jsmooth65 said:
When this has happened to me, going back and forth on the neutral t FINALLy engaged high range.
Thanks, does not seem to work, can engage transfer case high and low range manualy with motor removed, taken cover off motor, about to check the Electrical manual but it looks as if the motor is stuck
 

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Hi

The transfer motor is directly operated by the transferbox ECU. On the earlier models they have a ECU AMR 5254 which frequently fails as the power electronic components burn inside the ECU. It has been replaced by a different type of ECU with large cooling fins on the outside instead of the aluminum square box. If you take out the ECU and shake it and it rattles it is most likely burned. Opening the four screws at the bottom and peek inside will confirm it.

Further there is a sensor connected to the transferbox giving indication about the position. It is similar to the XYZ switch that is in the main gearbox operation lever and indicated in what gear is selected for the box. It is giving signals towards the ECU where the transferbox gear is located if I am not mistaken 5 different positions. Engaged high, between engaged and neutral, neutral, between engaged and neutral, engaged low. Failure of the right feedback from this sensor will get you the fault message as well. Check the wiring towards the sensor.

Of course it is also possible that the motor has burned.

best regards

Jos
 

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1995-2002 Range Rover P38A
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Discussion Starter #5
Jos Geuze said:
Hi

The transfer motor is directly operated by the transferbox ECU. On the earlier models they have a ECU AMR 5254 which frequently fails as the power electronic components burn inside the ECU. It has been replaced by a different type of ECU with large cooling fins on the outside instead of the aluminum square box. If you take out the ECU and shake it and it rattles it is most likely burned. Opening the four screws at the bottom and peek inside will confirm it.

Further there is a sensor connected to the transferbox giving indication about the position. It is similar to the XYZ switch that is in the main gearbox operation lever and indicated in what gear is selected for the box. It is giving signals towards the ECU where the transferbox gear is located if I am not mistaken 5 different positions. Engaged high, between engaged and neutral, neutral, between engaged and neutral, engaged low. Failure of the right feedback from this sensor will get you the fault message as well. Check the wiring towards the sensor.

Of course it is also possible that the motor has burned.

best regards

Thank you,
With the motor removed but still connected, managed to get it to activate twice after numerous attempts, checked the ECU connections, i will hook it up to text book in the morning before throwing parts at it, see if it is an actuator motor problem or something else like the ecu. In the mean time the select neutral message is still on dashboard but transfer case orange symbol turns off, and truck is now in low range for tomorrows trails and i can always remove the motor and manually shift it into high range if all else fails.


Jos
 

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I'll be there with tools soon, I'll see you in the lot. What color RR? (I'll look for the one with the hood up.... :)
 

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sorry I missed you, my group left at 8, right as I showed up. I'll be doing Ptarmigan pass (sp?) tomorrow, I'll keep an eye out for you in the morning, or send me an email through my site with your #
 

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Well it took me months to hunt down my transfer case problem. Mine wouldn't shift into LO, and would show "Select Neutral" on the display. Turns out it was a bad neutral safety switch. Try finding that wire (don't remember off hand), jumping it to ground, and see if the motor will shift. If so, there is your problem.

Just my 2 cents.
 

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Hi

Rave ETC:

CIRCUIT OPERATION 1
CIRCUIT OPERATION
Interface to transfer motor inside Transfer Box
(X313)
The Transmission Gearbox Control Unit (Z256) has
a seven wire interface to the Transfer Motor inside
the Transfer Box (X313), consisting of the four motor
position switches, the ground for the switches and
the drives to move the motor one way or the other.
Motor Position Switches–pins 17, 32, 33, 7
The Transmission Gearbox Control Unit (Z256)
reads the position of the motor in the form of a
binary Gray Code.
So the Transmission Gearbox Control Unit (Z256)
can find out in which gear the Transfer Box (X313) is
in and where the motor should move to, to engage
the desired range. If the Transfer Box (X313) moves
outside the normal modes (e.g. Left of High) then the
Transmission Gearbox Control Unit (Z256) can move
the motor back to the correct position.
Motor Position Switch ground–pin 19
The switches on the transfer box motor are
referenced to pin 19, i.e. if there is a problem with
the harness to pin 19 then the Transmission
Gearbox Control Unit (Z256) will not be able to
assess where the transfer motor is and so will not
move the motor.
Motor drive Clockwise (pins 25, 26) and Counter
Clockwise (pins 1, 2)
The Transmission Gearbox Control Unit (Z256)
receives signals from the motor position switches,
the drivers request, the vehicle speed and the
transmission neutral signal and, when the
parameters are correct, powers the motor from one
mode to another via the motor drives. This is actually
a single wire interface for each direction which is
split down to two wires at the Transmission Gearbox
Control Unit (Z256) to help pass the current though
two pins rather than one. If there is a problem with
either the motor drives or the harness, then the
motor will not move and a range change will not be
possible.
Vehicle Speed Sensor–pins 13, 30
The Transmission Gearbox Control Unit (Z256)
senses how fast the vehicle is travelling, compares
this speed to the value stored in the memory and
decides if a range change is allowed. Presently the
shift speeds are set at 5 mph High to Low and Low
to High on vehicles with an automatic transmission
and 15 mph Low to High on vehicles with a manual
transmission.
Interface to BeCM (Z238)
High, Low and Neutral Status Lamps
–pins 35, 14, 36
The Transmission Gearbox Control Unit (Z256)
informs the BeCM (Z238), which informs the
Instrument Pack (Z142), about the range the vehicle
is in via three status lamps.
When a range change is requested, the desired
range will flash up on the display (i.e. “HIGH”) and
continue flashing until the range change is achieved.
When complete, the range message will switch to
constant and be displayed for a few seconds.
If a range change is requested and not all of the
conditions are satisfied then the desired range
message will flash and continue flashing until all of
the parameters are satisfied or the request is
removed.
If the transfer box neutral is selected then, after a
five second safety delay, the Transfer Box (X313)
moves to neutral and the display shows “NEUTRAL”.
The High and Low status lamp signals also pass
information to the H–Gate and the Auto Gear Box
Control Unit (Z255).
Interface to Engine Control Module
(ECM) (Z132)
On North American Specification (NAS) vehicles, the
inability of the Transfer Gear Box ECU (Z256) to
move into the High range is flagged over the fault
output line. A fault will also be flagged in the event of
a speed sensor failure or incorrect transfer motor
position information. The Malfunction Indicator Lamp
(MIL) will illuminate if a fault is recorded on two
successive journeys.

from the workshop manual:

Transfer Box Electrical Components
Ratio control motor
The ratio control motor is located on the rear casing of
the transfer box and secured with four bolts. The
motor comprises a conventional single speed
permanent magnet type motor. The motor spindle has
a worm which engages with a worm wheel in a
housing at the end of the motor. The worm wheel is
attached to the spindle of the selector interlock spool
inside the transfer box.
The worm wheel also drives a motor encoder which
comprises four position switches. The transfer box
ECU provides a 5 V signal to each switch and
interprets the transfer box range by monitoring the
condition of each switch.
The transfer box ECU reads the motor position in the
form of a binary code with each switch either open or
closed circuit. The ECU measures between the
switches and an encoder ground on connector pin 19.
By using the combinations of the switches, the
transfer box ECU can calculate the transfer box
position and how the motor should operate to select
the desired range. If the transfer box should move to a
position outside the normal condition, i.e. left of high
range, the ECU can move the motor to the correct
position.
The table below shows the motor switch states and
the corresponding motor position for each state.
Switch 1 Switch 2 Switch 3 Switch 4 Motor position
Pin 17 Pin 32 Pin 31 Pin 7
Open Open Open Closed Left stop
Open Closed Open Closed Left of high
Closed Closed Open Closed High range
Closed Closed Closed Closed Right of high
Open Closed Closed Closed Zone 1
Open Closed Closed Open Neutral
Closed Closed Closed Open Zone 2
Closed Open Closed Open Low range
Closed Open Closed Closed Right stop
Speed sensor
The speed sensor is located in the rear casing and
secured with a screw. A toothed reluctor ring is
integrated on the rear output shaft. The inductive
speed sensor senses the reluctor ring and produces a
sine wave, impulse type signal as each tooth on the
reluctor ring passes the sensor.
The transfer box ECU processes the signal from the
speed sensor and compares this to a stored speed
value in the memory to determine if a range change is
allowed.
NOTE: The speed sensor is dedicated to
the transfer box ECU to determine if a
range change can be permitted.

Regards

Jos
 

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Discussion Starter #11
Test book not syncing with the RR
I will try again at the vendor night this afternoon

Thanks for the input.

Tried grounding pin 34 on gearbox ecu, does not help
Tried grounding pin 19 also. no change

Even if i put a fuse in #11 truck will still drive (should be in neutral for towing)
 

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Hi

Check your signals on the wires: 17, 32, 31, 7 then see what the position switch indicates. and check if all positions are giving the right signals. I know my previous text from RAVE is a bit messy without the table format etc.

AS you have been able to get it to work a few times it is almost certain (i.m.o) that the problem lies with the switch.

Regards

Jos
 

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Discussion Starter #13
Latest update,

Apparently when replacing transfer case shift motor , the transfer case ecu may also need to be replaced? :?

Showing an intermittent fault P1701 which i can clear with an OBD2 reader
Test book showing an intermittent reverse switch problem
In the mean time running trails in low range with no error messages, or select neutral messages, but unable to engage high range, except by removing transfer shift motor ( high range is clockwise with the gearbox in neutral of course) and the direction indicators / turn signals click audibly which they did not before.
Fuse 11 will still not put transfer case in neutral
 

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Hi

It is bolted onto the transfer case like the 4.0 and 4.6.

Regards

Jos
 

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so with fuse 11 inis it ment to be driveable or not as i have the same problem every time i select a gear it says select nutral also it seems to be stuck in lo and will not move to high but i can still drive it with fuse 11 in ?
 

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Fuse 11 moves the transfercase motor to a neutral position thus disengauging all drive functions. This is designed for four wheel down towing. You can certainly give it a try but if your tranfer motor is not working it won't do anything.
 

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you can remove the motor and shift it from high to low with a wrench (I belive, maybe it was a screwdriver)...

someone here has done it, i remember reading the thread.
 

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cheers i was told the moters are pop riveted on is that true its not like i can get under neath and look as the dame thing aint here with me :(
 
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