Page 3497 of 5267
LOW/REVERSE SWITCH VALVE
The low/reverse switch valve allows the low/reverse clutch to be operatedby either the LR/CC solenoid or the MS
solenoid.
REMOVAL
NOTE: The valve body can be removed for service without having to remove thetransmission assembly.
The valve body can be disassembled for cleaning and inspection of the individual components. (Refer to 21
- TRANSMISSION/AUTOMATIC - 45RFE/VALVE BODY - DISASSEMBLY)
1. Shift transmission into PARK.
2. Raise vehicle.
3. Disconnect wires at the solenoid and pressure
switch assembly connector.
4. Position drain pan under transmission oil pan.
5. Remove transmission oil pan.
6. Remove the primary oil filter (1) from valve body.
7. Remove bolts (1) attaching valve body to transmis-
sion case.
8. Lower the valve body and work the electrical con-
nector out of transmission case.
9. Separate the valve body from the transmission.
Page 3498 of 5267
DISASSEMBLY
1. Remove the bolts (1) holding the solenoid and
pressure switch assembly to the valve body. Do not
remove the screws on the top of the solenoid and
pressure switch assembly.
2. Separate the solenoid and pressure switch assem-
bly from the valve body.
3. Remove the screw holding the detent spring (2)
onto the valve body.
4. Remove the detent spring (2) from the valve body.
5. Remove the TRS selector plate (1) from the valve
body and the manual valve.
6. Remove the clutch passage seals (3) from the
valve body, if necessary.
Page 3503 of 5267
Inspect all the fluid seals on the valve body. Replace
any seals that are cracked, distorted, or damaged in
any way. These seals pass fluid pressure directly to
the clutches. Any pressure leak at these points, may
cause transmission performance problems.
Page 3506 of 5267
10. Install the TRS selector plate (1) onto the valve
body and the manual valve.
11. Position the detent spring (2) onto the valve body.
12. Install the screw to hold the detent spring (2) onto
the valve body. Tighten the screw to 4.5 Nꞏm (40
in. lbs.).
13. Install new clutch passage seals (3) onto the
valve body, if necessary.
14. Install the solenoid and pressure switch assembly
onto the valve body.
15. Install the bolts (1) to hold the solenoid and pres-
sure switch assembly onto the valve body. Tighten
the bolts to 6 Nꞏm (50 in. lbs.). Tighten the bolts
adjacent to the arrows cast into the bottom of the
transfer plate first.
Page 3508 of 5267

page page
AUTOMATIC TRANSMISSION - 48RE - GAS -
ELECTRICAL DIAGNOSTICS
DIAGNOSIS AND TESTING
P0711-TRANS TEMP SENSOR, NO TEMP
RISE AFTER START (GAS)................. 989
P0712-TRANS TEMP SENSOR VOLTAGE
TOO LOW (GAS)........................... 993
P0713-TRANS TEMP SENSOR VOLTAGE
TOO HIGH (GAS).......................... 999
P0720-LOW OUTPUT SPEED SENSOR -
RPM ABOVE 15 MPH (GAS)............... 1007
P0740-TORQ CON CLU, NO RPM DROP AT
LOCKUP (GAS)........................... 1013
P0743-TORQUE CONVERTER CLUTCH
SOLENOID/TRANS RELAY CIRCUITS. ..... 1017
P0748-PRESSURE SOL CONTROL/TRANS
RELAY CIRCUITS (GAS)................... 1024
P0751-O/D SWITCH PRESSED (LO) MORE
THAN 5 MINUTES........................ 1031
P0753-TRANS 3-4 SHIFT SOL/TRANS
RELAY CIRCUITS (GAS)................... 1034
P0783-3-4 SHIFT SOL, NO RPM DROP AT
LOCKUP (GAS)........................... 1041
P0850-P/N SWITCH PERFORMANCE
(GAS).................................... 1045
P128B-TCM POWER CONTROL CIRCUIT 2
LOW - TIPM.............................. 1050P128C-TCM POWER CONTROL CIRCUIT 2
HIGH - TIPM.............................. 1053
P128D-TCM POWER CONTROL CIRCUIT 2
OPEN - TIPM............................. 1056
P128E-TCM POWER CONTROL CIRCUIT 2
OVERCURRENT - TIPM................... 1059
P1740-TCC O/D SOL PERFORMANCE
(GAS).................................... 1063
P1756-GOV PRESS NOT EQUAL TO
TARGET @ 35 - 40 PSI (GAS)............. 1068
P1757-GOV PRESS ABOVE 3 PSI IN GEAR
WITH 0 MPH (GAS)....................... 1075
P1762-GOV PRESS SENSOR OFFSET
VOLTS TOO LOW OR HIGH (GAS)......... 1081
P1763-GOVERNOR PRESSURE SENSOR
VOLTS TOO HI (GAS)..................... 1087
P1764-GOVERNOR PRESSURE SENSOR
VOLTS TOO LOW (GAS)................... 1094
P1765-TRANS 12 VOLT SUPPLY RELAY
CTRL CIRCUIT (GAS)..................... 1099
STANDARD PROCEDURE
PRE-DIAGNOSTIC TROUBLE SHOOTING
PROCEDURE - 48RE GAS................. 1103
TRANSMISSION VERIFICATION TEST VER -
1(GAS).................................. 1104
Page 3511 of 5267

Theory of Operation
The Transmission Temperature Sensor is used to sense when the transmissiontemperatureistoohotortoocoldto
operate overdrive and/or the torque convertor clutch. When the transmission sensor detects a temperature below 0°
C (32° F), overdrive and the torque convertor clutch are disabled. When thedetected temperature is above 127° C
(260° F), overdrive is disabled and 3rd gear with TCC is engaged, this strategy is used to increase transmission
fluid flow to help cool the transmission.
When Monitored:
Continuously with the ignition on and the engine running.
Set Condition:
The DTC will set after two consecutive trips in which the transmission oil temperature is greater than 5° C (40°
F) and the transmission oil temperature does not rise more than 8° C (16° F) after 20 minutes of run time with
a vehicle speed greater than 48 Kmh (30 mph). The DTC will also set if the engine temperature is greater than
38° C (100° F) with the transmission oil temperature greater than 127° C (260° F).
Possible Causes
OTHER TRANSMISSION DTC’S SET
INTERMITTENT TRANSMISSION TEMPERATURE SENSOR
TRANSMISSION TEMPERATURE SENSOR
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.CHECK IF THE DTC IS CURRENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.
NOTE: It may be necessary to road test the vehicle to duplicate the originalset conditions.
With the scan tool, read Engine DTCs.
Did the DTC reset?
Ye s>>
Go To 2
No>>
Go To 6
2.CHECK FOR OTHER TRANSMISSION DTCS
Does the scan tool show any Park/Neutral DTCs?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom(s).
No>>
Go To 3
Page 3515 of 5267

Theory of Operation
The Transmission Temperature Sensor is used to sense when the transmissiontemperatureistoohotortoocoldto
operate overdrive and/or the torque convertor clutch. When the transmission sensor detects a temperature below 0°
C (32° F), overdrive and the torque convertor clutch are disabled. When thedetected temperature is above 127° C
(260° F), overdrive is disabled and 3rd gear with TCC is engaged, this strategy is used to increase transmission
fluid flow to help cool the transmission.
When Monitored:
Continuously with the ignition on and the engine running.
Set Condition:
The DTC will set if the monitored Transmission Temperature Sensor Signal circuit drops below 1.55 volts for
the period of 2.25 seconds.
Possible Causes
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO (K900) SENSOR GROUND
CIRCUIT
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND INSIDE
TRANSMISSION
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO THE (K900)SENSOR GROUND
CIRCUIT INSIDE TRANSMISSION
TRANSMISSION TEMPERATURE SENSOR
POWERTRAIN CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.CHECK IF THE DTC IS CURRENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.
NOTE: It may be necessary to road test the vehicle to duplicate the originalset conditions.
With the scan tool, read Engine DTCs.
Did the DTC reset?
Ye s>>
Go To 2
No>>
Go To 8
Page 3521 of 5267

Theory of Operation
The Transmission Temperature Sensor is used to sense when the transmissiontemperatureistoohotortoocoldto
operate overdrive and/or the torque convertor clutch. When the transmission sensor detects a temperature below 0°
C (32° F), overdrive and the torque convertor clutch are disabled. When thedetected temperature is above 127° C
(260° F), overdrive is disabled and 3rd gear with TCC is engaged, this strategy is used to increase transmission
fluid flow to help cool the transmission.
When Monitored:
Continuously with the ignition on and the engine running.
Set Condition:
This DTC will set if the (T54) Transmission Temperature Sensor Signal circuit voltage exceeds 3.76 volts for
the period of 2.2 seconds.
Possible Causes
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO (F856) 5-VOLT SUPPLY
CIRCUIT
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
(T54) 5-VOLT SUPPLY OPEN IN TRANSMISSION
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO (F856) 5-VOLT SUPPLY
CIRCUIT INTERNAL TO THE TRANSMISSION
(T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN INTERNAL TO THETRANSMISSION
(K900) SENSOR GROUND CIRCUIT OPEN INTERNAL TO THE TRANSMISSION
TRANSMISSION TEMPERATURE SENSOR
POWERTRAIN CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
1.CHECK IF THE DTC IS CURRENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.
NOTE: It may be necessary to road test the vehicle to duplicate the originalset conditions.
With the scan tool, read Engine DTCs.
Did the DTC reset?
Ye s>>
Go To 2
No>>
Go To 12