Page 2889 of 5267

7.(T50) L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
Ignition on, engine not running.
With the scan tool under TIPM, actuate the Transmission.
Measure the voltage of the (T50) L/R Pressure Switch Sense circuit.
Is the voltage above 0.5 volts?
Ye s>>
Repair the (T50) L/R PressureSwitch Sense circuit for a
short to voltage.
Perform 42RLE TRANSMISSION VERIFICATION TEST -
VER 1.
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/AU-
TOMATIC - 42RLE - STANDARD PROCEDURE)
8.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Test drive and verify if the transmission is launching in 2nd gear and/or noTCC engagement.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Are there 2nd gear launches and/or no TCC engagement?
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>>
Te s t C o m p l e t e .
Page 2890 of 5267
P1776-SOLENOID SWITCH VALVE LATCHED IN LR POSITION
For a complete wiring diagramRefer to Section 8W.
Page 2892 of 5267

3.CHECK TO SEE IF DTC P1776 IS CURRENT
With the scan tool, check the STARTS SINCE SET counter for P1776.
NOTE: This counter only applies to the last DTC set.
Is the status Active or is the STARTS SINCE SET counter 2 or less for this DTC?
Ye s>>
Go To 4
No>>
Go To 9
4.CHECK THE PCM AND WIRING USING THE TRANSMISSION SIMULATOR
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 switchtoL/R.
With the scan tool, monitor the L/R Pressure Switch State while pressing the Pressure Switch Test button.
Did the Pressure Switch state change from open to closed when the test button was pressed?
Ye s>>
Go To 5
No>>
Go To 6
5.CHECK THE SOLENOID SWITCH VALVE FOR STICKING
Remove the transmission oil pan and Valve body and inspect the Solenoid Switch Valve for sticking in its bore,
repair or replace as necessary.
NOTE: This DTC may be caused by debris lodged in the Transmission Solenoid Switch Valve bore. If debris
is found, clean the valve body and reassemble the transmission per the Service Information.
With the scan tool, record the DTC EVENT DATA for P1776 and erase DTCs.
Reassemble the transmission and test drive the vehicle. Try to duplicate the original set conditions using the DTC
EVENT DATA recorded earlier.
With the scan tool, check Transmission DTCs.
Did the DTC P1776 reset?
Ye s>>
Replace the Transmission Solenoid Assembly per the Service Information.
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
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Page 2894 of 5267

8.CHECK THE (T50) L/R PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE
Ignition on, engine not running.
With the scan tool under TIPM, actuate the Transmission.
Measure the voltage of the (T50) L/R Pressure Switch Sense circuit.
Is the voltage above 0.5 volts?
Ye s>>
Repair the (T50) L/R PressureSwitch Sense circuit for a
short to voltage.
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. Check for Service Information Tune-ups or
Service Bulletins for any possible causes that may apply. 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)
9.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Test Drive the vehicle and verify if the transmission is launching in 2nd gear and/or there is no TCC engagement.
With the scan tool, check the EVENT DATAto help identify the conditions in which the DTC was set.
Check for any Service Information Tune-ups or Service Bulletins for possible causes that may apply.
Are there 2nd gear launches and/or no TCC engagement?
Ye s>>
Disassemble and inspect the Valve Body per the Service Information Inspect the Solenoid Switch Valve
for sticking in its bore and repair or replace 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 .
Page 2895 of 5267

P1790-FAULT IMMEDIATELY AFTER SHIFT
For a complete wiring diagramRefer to Section 8W.
When Monitored:
After a Gear Ratio Error code is stored.
Set Condition:
After a Gear Ratio Error DTC has already been set. The DTC is set if the fault happened within 1.3 seconds
of a shift. The DTC set time will vary from 1.214 seconds to 15 seconds.
Possible Causes
FAULT AFTER SHIFT
Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Theory of Operation
This DTC is not stored alone. It is stored if a Gear Ratio DTC is detected immediately after shift. The existence of
DTC P1790 indicates a mechanical or hydraulic (not electrical) related problems. It should be noted, however, that
all mechanical problems don’t necessarily result in DTC P1790. When this DTC exists, diagnosing the system
should be based on the associated DTC and only mechanical causes should be considered.
Diagnostic Test
1.FAULT AFTER SHIFT
This DTC is set along with a Gear Ratio DTC. Perform the appropriate test forthe Gear Ratio DTC stored.
NOTE: Check Pending DTCs or 1 trip failures if there are no Active or Stored Gear Ratio DTCs.
If there are no possible causes remaining, view repair.
Repair
Refer to the Transmission category and perform the appropriate symptom.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)
Page 2896 of 5267
P1794-SPEED SENSOR GROUND ERROR
For a complete wiring diagramRefer to Section 8W.
Page 2897 of 5267

When Monitored:
Every 7msec after a controller reset with transmission in neutral.
Set Condition:
After a PCM reset in neutral and Input and Output sensor ratio equals 2.50 to1.0 ± 50.0 RPM.
Possible Causes
SPEED SENSOR GROUND CIRCUIT OPEN
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 input and output speed sensors use a common ground circuit. The loss of this common ground results in the
input signal being sensed for both. After a reset in neutral, and after observing a specific ratio, the Speed Check
Fault Counter will increment. Because the speed sensors and the thermistor share the same ground circuit, this
DTC may indicate a loss of the common speed sensor ground. In some cases thisfault will cause a Gear Ratio
Error DTC to be set.
Diagnostic Test
1.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 8333-1A.
Ignition on, engine not running.
With the Transmission Simulator, set the
Input/Output Speedswitch toONand the rotary switch to the3000/
1250
position.
With the scan tool, monitor the Input and Output Speed Sensor readings.
Does the Input Speed read 3000 RPM and the Output Speed read 1250 RPM, ± 50 RPM?
Ye s>>
Go To 2
No>>
Go To 3
Page 2898 of 5267

2.(T13) SPEED SENSOR GROUND CIRCUIT OPEN
Turn the ignition off to the lock position.
Disconnect the PCM C4 harness connector.
Disconnect the Input and Output Speed Sensor harness connectors.
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 both of the (T13) Speed Sensor Ground cir-
cuits from the appropriate terminal of special tool #8815 to the Input
and Output Speed Sensor harness connectors.
Is the resistance above 5.0 ohms on either circuit?
Ye s>>
Repair the (T13) Speed Sensor Ground circuit for an open.
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)
3.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 .