transfer case faults

[dutchie2002]

Hello

i run a 4.6 eddy bauer and i am having problems with the transmission. the check transmission light starts flashing and when i scan it it comes up with codes p1867 and p1891 reading the forum i replaced the transfercase shifter motor. now after clearing the codes they came back on cruising at a steady speed. at standstill i can go through all the modes of the 4x4 system without a problem and when driving it is fine but then at cruising at a steady speed i get the same codes coming back with the flashing transmission light. could anyone on here help me this please

 

[BrooklynBay]

Maybe the transfer case has internal damage?

 

[dutchie2002]

hello

thanks for your answer.

i haven’t opened it up yet but did do an oil change which came out pretty clean with no debris. it also has full ford history with only 60k miles so i am hopeful it’s good mechanically.
i had it of the floor with all 4 wheels and it shifts through all the modes ok with no strange sounds.
i just found it strange that it works faultless if i drive it in town traffic but the it faults when i cruise it at constant speed for a while.
is there a document which explains how the auto 4x4 works

 

[wollimann]

p1867 (Transfer case contact plate general circuit failure)
p1891 (Transfer Case Contact Plate Ground Return Open Circuit)

ford history with only 60k miles so i am hopeful it’s good mechanically.

Your TC will be fine inside, but the codes tells you there's a electronical issue.
(As i have a flashing 4x4 light, one of the two sensors was bad/cracked)

reading the forum i replaced the transfercase shifter motor.

Replaced it with a used/new/refurbished TC shift motor? Brand?
These shift motors have some trouble with their end position switch and the contacts inside
(corrosion/alignmet).

Unfortunately i am not familiar in diagnosting DTC's, but first i would look at plugs and contacts.
Maybe pull the sensors and look for cracks.

Speed Sensor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Looking at the TC connector, all wires at their matching position? Any corrosion?

Transfer Case Shift Motor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

is there a document which explains how the auto 4x4 works

Transmission and Drivetrain: Description and Operation — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Regards Wolfgang

 

[dutchie2002]

p1867 (Transfer case contact plate general circuit failure)
p1891 (Transfer Case Contact Plate Ground Return Open Circuit)


Your TC will be fine inside, but the codes tells you there's a electronical issue.
(As i have a flashing 4x4 light, one of the two sensors was bad/cracked)
View attachment 464044

Replaced it with a used/new/refurbished TC shift motor? Brand?
These shift motors have some trouble with their end position switch and the contacts inside
(corrosion/alignmet).

Unfortunately i am not familiar in diagnosting DTC's, but first i would look at plugs and contacts.
Maybe pull the sensors and look for cracks.

Speed Sensor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Looking at the TC connector, all wires at their matching position? Any corrosion?

Transfer Case Shift Motor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Transmission and Drivetrain: Description and Operation — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Regards Wolfgang

hello wolfgang

thanks for that reply

i am still not on top of this fault.

if i am city driving it’s faultless only when i am cruising a steady speed atvsay 45 mph it comes up with a fault but the car keeps on driving fine.
when i test the new shiftmotor at standstill going through all the transmission modes all the feedback switches seem to be working as they should. i have checked the wiring and can’t find any faults with that.
both the original shift motor and the new one from rock auto give the same issue.
i tried the brown wire trick but didn’t work either.
i really don’t know what to do next.
have you got any more suggestions?
can i do away with the auto 4x4 in some way?

 

[wollimann]

i tried the brown wire trick but didn’t work either.
i really don’t know what to do next.
have you got any more suggestions?
can i do away with the auto 4x4 in some way?

Where and how did you interrupt the brown wire with a switch? Wire diameter? Contacts soldered or crimped?
I am not sure, but your issue could be a resistance problem.
Saw this video and there is a groud wire connected to the shift motor, connection ok?

Did you inspect the two sensors for cracks?

If you like to fight with pinpoint tests

Test I: The Vehicle Does Not Shift Between Auto/4WD High And Low Modes Correctly — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

 

[dutchie2002]

p1867 (Transfer case contact plate general circuit failure)
p1891 (Transfer Case Contact Plate Ground Return Open Circuit)


Your TC will be fine inside, but the codes tells you there's a electronical issue.
(As i have a flashing 4x4 light, one of the two sensors was bad/cracked)
View attachment 464044

Replaced it with a used/new/refurbished TC shift motor? Brand?
These shift motors have some trouble with their end position switch and the contacts inside
(corrosion/alignmet).

Unfortunately i am not familiar in diagnosting DTC's, but first i would look at plugs and contacts.
Maybe pull the sensors and look for cracks.

Speed Sensor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Looking at the TC connector, all wires at their matching position? Any corrosion?

Transfer Case Shift Motor — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Transmission and Drivetrain: Description and Operation — 2002 Ford Explorer 4WD V8-4.6L VIN W Service Manual | Operation CHARM

Detailed repair manual for the 2002 Ford Explorer 4WD V8-4.6L VIN W.

charm.li

Regards Wolfgang

Hello Wolfgang

thank you for the info.

i am still struggling with this fault.

the shift motor is a new one from rockauto.

when i drive it with the scanner plugged in both shaft speeds seem ok.

what i did notice on the 4 switches in the new motor is that they are all open. then when i do shifting say from auto to permanent 4x4 some of the switches close when the motor is shifting but after that they return to open again whilst it is in 4x4. if i then switch to 4x4 low some will close again but then return to all 4 open after a few seconds. the car does shift between the modes.

is it normal that the switches all go back to open even though the tb is in a different position