When Monitored:
Continuously while driving in a forward gear.
Set Condition:
The PCM continuously monitors Actual Line Pressure. If the Actual Line Pressure reading is greater than the
highest Desired Line Pressure ever used in the current gear, while the Pressure Control Solenoid duty cycle is
at or near its maximum value (which should result in minimum line pressure), the DTC will set.
Possible Causes
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
LINE PRESSURE SENSOR CONNECTION
(T118) PRESSURE CONTROL SOLENOID CONTROL CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T118) PRESSURE CONTROL SOLENOID CONTROL CIRCUIT SHORT TO GROUND
TRANSMISSION CONTROL OUTPUT CIRCUIT
LINE PRESSURE SENSOR
STUCK OR STICKING MAIN REGULATOR VALVE
POWERTRAIN CONTROL MODULE
Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Theory of Operation
Line pressure is measured by the Line Pressure Sensor (LPS) and regulationis achieved by changing the duty
cycle of the Pressure Control Solenoid (PCS) controlled by the Transmission Control System. (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 both the engine and transmission.
The Transmission Control System calculates torque input to the transmission and uses it as the primary input to the
desired line pressure calculation. This is called Torque Based Line Pressure. In addition, the line pressure is set to
a preset level 827 or 931 kPa (120 or 135 psi) during shifts and in Park and Neutral to ensure consistent shift
quality. The desired line pressure is continuously being compared to the actual line pressure. If the actual line pres-
sure is consistently higher than the highest desired line pressure ever used in the current gear, the line pressure
high DTC P0869 will set.
Diagnostic Test
1.CHECKFORRELATEDDTC’S
With the scan tool, check for other Transmission DTC’s
Are there any line pressure sensor or transmission relay output DTCs present also?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
2.CHECK IF THE DTC IS CURRENT
With the scan tool, check the STARTS SINCE SET counter for P0869.
Is the STARTS SINCE SET COUNTER 2 or less?
Ye s>>
Go To 3
No>>
Go To 9
3.CHECK THE PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator,Miller tool #8333 and the ElectronicTransmission Adapter kit.
With the Transmission Simulator select the
OFFposition on theInput/Output Speedswitch.
Ignition on, engine not running.
With the scan tool, monitor the Line Pressure during the following step.
Using the Transmission Simulator, set the rotary switch to each of the 3 line pressure positions.
NOTE: All three scan tool Line Pressure readings should be steady and ± 14 kPa or 2.0 psi of the reading
specified on the Transmission Simulator.
Did the Line Pressure read within ± 14 kPa or 2.0 psi in all three positions?
Ye s>>
Go To 4
No>>
Go To 5
4.CHECK THE LINE PRESSURE SENSOR CALIBRATION
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit and reconnect
all previously disconnected connectors.
Install the Line Pressure Gauge, Miller tool #C-3293, 0 to 2000 kPa or 0 to 300 psi in the L/R pressure port.
Start the engine in park.
Monitor the Line Pressure readings on the scan tool and the pressure gauge.
Compare the Line Pressure readings between the scan tool and the pressure gauge.
Is the pressure gauge reading within 34 kPa or 5 psi of the scan tool reading?
Ye s>>
Repair the internal transmission and inspect the Transmission Oil Pump per the Service Information and
replace if necessary. If no problem is found, replace the Pressure ControlSolenoid.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Replace the Line Pressure Sensor per the Service information.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
9.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Where there any problems found?
Ye s>>
Repair as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
When Monitored:
In any forward gear with engine speed above 1000 RPM, shortly after a shift and every minute thereafter.
Set Condition:
After a shift into a forward gear, with engine speed greater than 1000 RPM, the PCM momentarily turns on
element pressure to the clutch circuits that don’t have pressure to identify the correct pressure switch closes.
If the pressure switch does not close 2 times the DTC sets.
Possible Causes
LOSS OF PRIME P0944 PRESENT
(T16) TRANSMISSION CONTROL OUTPUT CIRCUIT OPEN
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
(T9) OD PRESSURE SWITCH CIRCUIT SHORT TO GROUND
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/PRESSURE SWITCH ASSEMBLY
INTERNAL TRANSMISSION
POWERTRAIN CONTROL MODULE
Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Theory of Operation
Pressure switches are normally off or open (no pressure applied) and read high (+12 volts). When an element is
applied, the corresponding pressure switch closes to ground (0 volts) or turns on. The controller tests the OD and
2/4 pressure switches when they are off (when the corresponding friction element is not applied) by briefly applying
the OD and 2/4 elements which will cause the corresponding pressure switchto close. The test verifies that the
switches are operational and that the switch will close when the corresponding element is applied. If a switch fails
to respond, it is re-tested. The MIL illuminates and the transmission system defaults to Limp-in mode.
Diagnostic Test
1.CHECKING FOR LOSS OF PRIME DTC
With the scan tool, check for other Transmission DTCs.
Is the DTC P0944 present also?
Ye s>>
Refer to the Transmission category and perform the appropriate diagnostic procedure.
No>>
Go To 2
2.CHECK FOR RELATED TRANSMISSION DTCS
With the scan tool, read Transmission DTCs.
Are any of the DTCs P0732, P0734 and/or P0846 present also?
Ye s>>
Replace the Transmission Solenoid/Pressure Switch Assembly per the Service Information.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 3
3.CHECK TO SEE IF DTC P0870 IS CURRENT
With the scan tool, view DTCs.
Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?
Ye s>>
Go To 4
No>>
Go To 9
4.PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator,Miller tool #8333 and the ElectronicTransmission Adapter kit.
Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector switchtoOD.
With the scan tool, monitor the UD Pressure Switch state while pressing thePressure Switch Test button on the
Transmission Simulator.
Wiggle the wires leading to the PCM while pressing and holding the PressureSwitch Test button.
Did the OD Pressure Switch state change to closed and remain closed while wiggling the wires?
Ye s>>
Disassemble and inspect the Valve Body per the Service Information and repair or replace as neces-
sary. If no problems are found in the Valve Body, replace the Transmission Solenoid/Pressure Switch
Assembly.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 5
5.(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
Turn the ignition off to the lock position.
Disconnect the PCM C4 harness connector.
Disconnect the Transmission Solenoid/Pressure Switch Assembly har-
ness connector.
NOTE: Check connectors - Clean/repair as necessary.
CAUTION: Do not probe the PCM harness connectors. Probing the
PCM harness connectors will damage the PCM terminals resulting
in poor terminal to pin connection. Install Miller tool #8815 to per-
form diagnosis.
Measure the resistance of the (T9) OD Pressure Switch Sense circuit
between the Transmission Solenoid/Pressure Switch Assembly harness
connector and the appropriate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (T9) OD Pressure Switch Sense circuit for an
open.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 6
8.(T16) TRANSMISSION CONTROL OUTPUT CIRCUIT OPEN
With the scan tool under TIPM, actuate the Transmission.
Using a 12-volt test light connected to ground, check (T16) Transmis-
sion Control Output circuit in the Transmission Solenoid/Pressure
Switch Assembly harness connector.
NOTE: The test light must illuminate brightly. Compare the bright-
ness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Ye s>>
Using the schematics as a guide, check the Powertrain
Control Module (PCM) terminals for corrosion, damage, or
terminal push out. Pay particular attention to all power and
ground circuits. If no problems are found, replace the PCM
per the Service Information.With the scan tool, perform
QUICK LEARN
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Repair the (T16) Transmission Control Relay Output circuit
for an open. If the fuse is open make sure to check for a
short to ground.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
9.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
When Monitored:
Whenever the engine is running.
Set Condition:
The DTC is set if one of the pressure switches are open or closed at the wrong time in a given gear. If the
problem is identified for 3 successive key starts, the transmission will go into Limp-in mode and the MIL will
turn on after 10 seconds of vehicle operation.
Possible Causes
RELATED TIPM TCM POWER INPUT DTCS PRESENT
LOSS OF PRIME DTC PRESENT
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/PRESSURE SWITCH ASSEMBLY
POWERTRAIN CONTROL MODULE
Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Theory of Operation
The Transmission system uses three pressure switches to monitor the fluidpressure in the LR, 2/4, and OD ele-
ments. The pressure switches are continuously monitored for the correct states in each gear. Normal operation will
be experienced if no other codes are present. Transmission Control Systemwill ignore the code. Limp-in condition
will only occur if DTC P0871 is present with a DTC P0706.
PRESSURE SWITCH STATES
GEAR L/R 2/4 OD
ROPOPOP
P/N CL OP OP
1st CL OP OP
2nd OP CL OP
DOPOPCL
OD OP CL CL
OP = OPEN
CL = CLOSED
Diagnostic Test
1.CHECK FOR TIPM TCM POWER INPUT DTCS
With the scan tool under TIPM, check for TCM Power Input DTCs.
Are there any TIPM TCM Power Input DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate diagnostic procedure.
No>>
Go To 2
2.CHECK FOR LOSS OF PRIME DTC
With the scan tool, check for other Transmission DTCs.
Is the DTC P0944 present also?
Ye s>>
Refer to the Transmission category and perform the appropriate diagnostic procedure.
No>>
Go To 3
3.CHECK TO SEE IF P0841 IS CURRENT
With the scan tool, view DTCs.
Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?
Ye s>>
Go To 4
No>>
Go To 8
4.PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator,Miller tool #8333 and the ElectronicTransmission Adapter kit.
Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector to OD.
With the scan tool , monitor the OD Pressure Switch state while pressing thePressure Switch Test button on the
Transmission Simulator.
Did the OD Pressure Switch state change?
Ye s>>
Replace the Transmission Solenoid/Pressure Switch Assembly per the Service Information.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 5