No low range again today
My temp fix must have been a coincidence.
Removed the "The Final Drive Control Module" inspected for signs of "the crack" none found.
had a read of this
http://www.jeepforum.com/forum/f67/n...7/index13.html
It seams that in most cases the fix is to replace the Transfer Case Actuator.
http://www.justanswer.com/jeep/835jb...-cherokee.html
Quote:
Symptom/Vehicle Issue:
Diagnostic Trouble Code C140F “Transfer Case Range Position Sensor Erratic Performance”
After Performing Recall N23
Discussion:
The Final Drive Control Module (FDCM) monitors the transfer case position sensor for two erratic
performance failures.
1. Position sensor drift to higher voltages during the drive cycle.
2. A difference between the encoder position value detected at first key on cycle compared to the
value stored into memory during the previous key off event.
Either failure mode will result in the setting of a permanent C140F fault. Once set, this fault will
remain active until the 4WD system is repaired. The “Service 4WD” indicator in the instrument cluster
will not illuminate when this fault sets until the customer attempts a range shift (between 4WD High
and 4WD Low, or Neutral).
Diagnosis:
1. Confirm the integrity of the Transfer Case shift motor wiring harness. Any circuit faults present
must be addressed prior to repairing the C140F fault. It is possible that both a C140F (Erratic
Encoder Performance Fault) and a C1405 fault (T-case range position sensor circuit high fault)
may be set due to the failure of the actuator. However, continuity of each circuit and checks
for short to ground and shorted circuit to circuit should be checked for each circuit of the TCase
interface.
2. Replace the actuator on the Transfer Case. Using the diagnostic tool, confirm that the position
sensor reading is 2.84 volts +/- 0.04. (FDCM / Read Write Data).
Parts Required:
AR (1) 05143786AA Actuator, Transfer Case
STAR Case
This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Center
Online does not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear
to be similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate
course of action.
Chrysler Group LLC Contact the STAR Center for assistance if no solution is found Version 05/23/13
NOTE: THE ACTUATOR IS SHIPPED IN THE PROPER 4WD HIGH RANGE LOCATION.
THE ACTUATION STUB SHAFT ON THE T-CASE (NOT THE ACTUATOR) NEEDS
TO BE INDEXED TO THE PROPER POSITION IN ORDER TO INSTALL THAT
ACTUATOR. DO NOT DRIVE THE SHIFT MOTOR WITH A BATTERY TO ALIGN
THE ACTUATOR POSITION WITH THE T-CASE POSITION. THE T-CASE
ACTUATOR STUB SHAFT SHOULD BE MOVED (CAREFULLY WITH CHANNEL
LOCK PLIERS) TO ALIGN WITH THE ACTUATOR.
Repair Procedure:
1. Replace the actuator. Refer to the procedures identified in the appropriate Service Information
for additional information.
2. Perform a key cycle (Key ON and then key OFF). Allow sufficient time for the FDCM and the
entire vehicle bus to go to sleep. To be sure the entire vehicle bus to go to sleep, disconnect
all diagnostic tools from the vehicle, turn off the key, and remove key from the ignition. Close
all doors. Wait 5 minutes.
3. After performing the key cycle, DO NOT attempt to shift the transfer case using the customer
switch. This will prevent the C140F fault from clearing later.
4. Re-connect the diagnostic tool and cycle the key ON.
5. Select the FDCM, and issue the clear faults command two times. It is required to issue the
clear faults command twice.
6. After approximately 6 seconds, the C140F fault will de-mature to a “Stored” status. Confirm
that the diagnostic tool reports that the C140F fault is in a stored status (not “Active”). If after
30 seconds the fault is not in a stored status, return to step 3 and try again.
7. Once the C140F fault is in a stored status, perform one additional “Clear Faults” command.
This will completely remove the fault from the FDCM memory and return the 4WD system to
an operational status.
8. Perform a T-Case range shift to confirm that the 4WD system will shift to 4WD Low Range.
Shift the T-Case back to 4WD High Range. Repair complete. |
From what I read from Jeepforum.com once you get the Service 4wd System on the dash you wont be able to select 4Low until the code it throws is cleared (code C140F), mil light will not be on.
The US guys have had success clearing the code with a Superchips tuner (maybe the green diesel one will work as well) &
http://www.autoenginuity.com/