3.CHECK FOR INTERMITTENT OPERATION
The conditions to set this DTC are not current at this time.
Check the gearshift linkage adjustment.
Gear ratio DTC’s can be set by problems in the Input and Output Speed Sensor circuits. If the vehicle passes the
Clutch Test and still sets a Gear Ratio DTC, check the Speed Sensors for proper operation.
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.
Check the wiring and connectors for the Speed Sensors for a good connection, then perform a wiggle test using the
Transmission Simulator.
This DTC can also be set under extreme temperature conditions, this is usually caused by an internal problem.
Verify if the problem is only experienced under extreme hot or cold conditions.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.
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 .
4.CHECKFORRELATEDPRESSURESWITCHDTCS
With the scan tool, read Transmission DTC’s.
Are the DTC’s P0870 and/or P0871 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>>
Repair internal Transmission per the Service Information. Check all of the components related to the
O/D and 2/4 clutches. Inspect the Oil Pump and repair or replace as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
P0736-GEAR RATIO ERROR IN REVERSE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
The Transmission gear ratio is monitored continuously while the transmission is in gear.
Set Condition:
If the ratio of the Input RPM to the Output RPM does not match the current gearratio when compared to the
known gear ratio.
Possible Causes
RELATED TRANSMISSION DTCS PRESENT
INTERMITTENT GEAR RATIO ERRORS
INTERNAL TRANSMISSION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Theory of Operation
The transmission system uses two speed sensors, one to measure input RPM and one to measure output RPM.
These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through
data checks. When in gear, if the gear ratio does not compare to a known gear ratio, the corresponding gear ratio
error trouble code is set. The transmission will go into Limp-in mode afterfour gear ratio error events occur in a
given driving cycle.
Diagnostic Test
1.DETERMINING IF RELATED TRANSMISSION DTCS ARE PRESENT
With the scan tool, read Transmission DTCs.
If any of these DTCs are present, perform their respective tests first.
Are there any Loss of Prime, Line Pressure Sensor and/or Speed Sensor DTCs present?
Ye s>>
Refer to appropriate diagnostic procedure in the Transmission category.If any of these DTCs are
present, they will cause a gear ratio error. Perform the test for Loss of Primefirstifitispresent.
No>>
Go To 2
2.CHECK TO SEE IF P0731 IS CURRENT
With the scan tool, perform the Reverse gear clutch test. Follow the instructions on the scan tool.
Increase the throttle angle or TPS Degree to 30° for no more than a few seconds.
CAUTION: Do not overheat the transmission.
Did the Clutch Test pass, Input Speed remain at zero?
Ye s>>
Go To 3
No>>
Repair internal Transmission per the Service Information. Check all of the components related to the
Reverse and LR clutches. Inspect the Oil Pump and repair or replace as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
3.CHECK FOR INTERMITTENT OPERATION
The conditions to set this DTC are not current at this time.
Check the gearshift linkage adjustment.
Gear ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits. If the vehicle passes the
Clutch Test and still sets Gear Ratio DTC, check the Speed Sensors for proper operation.
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.
Check the wiring and connectors related to the Speed Sensors for a good connection, then perform a wiggle test
using the Transmission Simulator.
This DTC can also be set under extreme temperature conditions, this is usually caused by an internal problem.
Verify if the problem is only experienced under extreme hot or cold conditions.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.
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:
Continuously while driving in a forward gear.
Set Condition:
The PCM continuously monitors Actual Line Pressure and compares it to DesiredLinePressure.IftheActual
Line Pressure is more than 10 psi below Desired Line Pressure, this DTC willset.
Possible Causes
CHECK FOR RELATED DTC’S
LOW FLUID LEVEL
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO VOLTAGE
(T118) PRESSURE CONTROL SOLENOID CONTROL CIRCUIT SHORT TO ANOTHER CIRCUIT
INTERNAL TRANSMISSION
LINE PRESSURE SENSOR
CRACKED, PLUGGED, OR MIS-INSTALLED PRIMARY OIL FILTER
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 lower than the target while driving, the line pressure low DTC P0868 will set.
Diagnostic Test
1.CHECKFORRELATEDDTCS
With the scan tool, check for other transmission DTCs
Is the DTC P0932 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 P0868.
NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET COUNTER 2 or less?
Ye s>>
Go To 3
No>>
Go To 10
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.
On the Transmission Simulator select the
OFFposition of theInput/Output Speedswitch.
Ignition on, engine not running.
With the scan tool, monitor the Line Pressure during the following steps.
Using the Transmission Simulator, set the rotary knob 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 6
4.CHECK THE LINE PRESSURE SENSOR
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333 and reconnect all previously disconnected connectors.
Install a Pressure Gauge, 0 to 2000 kPa or 0 to 300 psi to the L/R test port.
Start the engine in park.
Monitor the line pressure readings of both the scan tool and the pressure gauge and compare the two readings.
Is the line pressure gauge reading within 34 kPa or 5 psi of the scan tool reading?
Ye s>>
Go To 5
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)
5.CHECK FOR A PLUGGED TRANSMISSION OIL FILTER
Turn the ignition off to the lock position.
Remove and inspect the Transmission Oil Pan for excessive debris per the Service Information.
Remove and inspect the Transmission Oil Filter per the Service Information.
Does the Oil Pan contain excessive debris and/or is the Transmission Oil Filter plugged?
Ye s>>
Repair as necessary. If the Transmission Oil Filter is plugged or there is excessive debris, refer to the
Service Information for the proper Hydraulic repair procedure.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Repair internal transmission and inspect the Transmission Oil Pump per the Service Information and
replace if necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
6.CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
Disconnect the Transmission Simulator, Miller tool #8333 and the Elec-
tronic Transmission Adapter kit.
Reconnect all previously disconnected connectors except the Line Pres-
sure Sensor/Variable Force Solenoid Assembly harness connector.
Ignition on, engine not running.
Measure the voltage of the (F856) 5-volt Supply circuit.
Is the voltage above 5.5 volts?
Ye s>>
Repair the (F856) 5-volt Supply circuit for a short to voltage.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 7
7.CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the PCM C1 harness connector and connect Miller tool
#8815.
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 (F856) 5-volt Supply circuit between the
Line Pressure Sensor/Variable Force Solenoid Assembly harness con-
nector and the appropriate terminal of Miller tool #8815.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the (F856) 5-volt Supply circuit for an open.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 8
8.CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (F856) 5-volt Supply
circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (F856) 5-volt Supply circuit for a short to ground.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
Go To 9
9.CHECK THE (T118) PRESSURE CONTROL SOLENOID CONTROL CIRCUIT FOR A SHORT TO ANOTHER
CIRCUIT
Turn the ignition off to the lock position.
Disconnect the Line Pressure Sensor/Variable Force Solenoid Assembly
harness connector.
Disconnect all PCM harness connectors.
Measure the resistance between the (T118) Pressure Control Solenoid
Control circuit and all other circuits in the Line Pressure Sensor/Variable
Force Solenoid Assembly harness connector.
Is the resistance below 5.0 ohms between the (T118) Pressure
Control Solenoid Control circuit and any other circuit(s) in the
Line Pressure Sensor/Variable Force Solenoid Assembly har-
ness connector?
Ye s>>
Repair the (T118) Pressure Control Solenoid Control circuit
for a short to another circuit(s).
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
No>>
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/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
10.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 .