Content .. 1166 1167 1168 1169 ..
Jeep Liberty KJ. Manual - part 1168
•
When Monitored:
Continuously with ignition on and engine running.
•
Set Condition:
This DTC will set if the monitored Line Pressure Sensor voltage is greater than or equal to 4.75 volts for the
period of 0.18 seconds
Possible Causes
(T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT OPEN
(Z133) SENSOR GROUND CIRCUIT OPEN
(T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
LINE PRESSURE SENSOR
TRANSMISSION CONTROL MODULE
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
Line pressure is electronically controlled by the Transmission Control System and is measured by the Line Pressure
Sensor (LPS). The desired line pressure is continuously being compared to the actual line pressure and is regulated
by electronically changing the duty cycle of the Pressure Control Solenoid (PCS). (5% duty cycle = solenoid off =
max line pressure, 62% duty cycle = solenoid on = min line pressure).
The Transmission Control System calculates the desired line pressure based on inputs from the transmission and
engine. A calculated torque input to the transmission is used as the primary input of the desired line pressure cal-
culation and is called Torque Based Line Pressure. In addition, the line pressure is set to a preset level 827 to 931
kPa (120 to 135 PSI) during shifts and in Park and Neutral to ensure consistent shift quality.
The monitored Line Pressure Sensor voltage should always be between 0.35 and 4.75 volts. Any monitored volt-
ages outside these parameters indicate an Line Pressure Sensor or wiring problem and will cause either DTC
P0934 or P0935 to set.
Diagnostic Test
1.
CHECK TO SEE IF DTC IS CURRENT
With the scan tool, Check the STARTS SINCE SET counter for P0935.
NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET counter 2 or less?
Yes
>> Go To 2
No
>> Go To 6
2.
TCM AND WIRING
Turn the ignition off to the lock position.
Remove the Starter Relay.
CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.
WARNING: The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury
or death.
NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.
Install the Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the scan tool, monitor the Line Pressure.
Using the Transmission Simulator, set the rotary switch to each of the 3 line pressure positions.
21 - 616
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
KJ