Theory of Operation
The Governor Pressure Control System is used to regulate the governor pressure which controls the shifts for first,
second, and third gear. The Governor Pressure Control System test verifies that the requested pressure and the
actual pressure are within a predetermined tolerance.
When Monitored:
While the engine is running and the gear selector is in the Drive position.
Set Condition:
This DTC will set if the monitored Governor Pressure is greater than 41.4 kPa(6psi)for5secondswhilethe
gear selector is in the Drive position with the road speed equal to zero - sixtimes during a drive cycle. The
transmission oil temperature must be between 23 - 88° C (73 - 190° F).
Possible Causes
OTHER TRANSMISSION DTC’S PRESENT
5 VOLT SUPPLY CIRCUIT OPEN
5 VOLT SUPPLY CIRCUIT OPEN INSIDE THE TRANSMISSION
TRANSMISSION OIL BURNT OR OIL PAN HAS EXCESSIVE DEBRIS - INTERNAL TRANSMISSION DAMAGE
GOVERNOR PRESSURE SENSOR
GOVERNOR PRESSURE SOLENOID
VA LV E B O D Y
ENGINE CONTROL MODULE 5 VOLT SUPPLY
ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.OTHER TRANSMISSION DTC’S PRESENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Are there any other Transmission DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom(s).
No>>
Go To 2
2.CHECK IF THE DTC IS CURRENT
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 3
No>>
Go To 11
3.CHECKING FOR GOVERNOR PRESSURE ABOVE 6 PSI
Start the engine.
CAUTION: Apply the parking brake.
Warm the transmission to a normal operating temperature above 43° C (110° F).
CAUTION: Firmly apply the brakes.
With the engine RPM at idle, place the gear selector in Drive.
With the scan tool, read the governor pressure.
Is the governor pressure above 41.4 kPa (6 psi)?
Ye s>>
Go To 4
No>>
Go To 11
4.GOVERNOR PRESSURE MATCH GAUGE PRESSURE
Turn the ignition off to the lock position.
Install a 700 kPa (100 psi) pressure gauge to the Governor Pressure Test Port. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
Start the engine.
Warm the transmission to a normal operating temperature above 43° C (110° F).
CAUTION: Firmly apply the brakes.
With the engine RPM at idle, place the gear selector in Drive.
With the scan tool, read the governor pressure and compare the scan tool reading to the pressure gauge reading.
Does the scan tool Governor Pressure reading match the pressure gauge reading within 6.9 kPa (1
psi)?
Ye s>>
Go To 5
No>>
Go To 8
5.CHECK FOR BURNT TRANSMISSION FLUID AND/OR EXCESSIVE DEBRIS IN THE TRANSMISSION OIL
PA N
Turn the ignition off to the lock position.
Remove the transmission oil pan per the Service Information and inspect for burnt transmission fluid and excessive
debris. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID - STANDARD PROCEDURE)
Is the transmission fluid burnt or does the transmission oil pan contain excessive debris?
Ye s>>
Repair internal transmission as necessary. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC -
48RE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 6
6.REPLACE THE GOVERNOR PRESSURE SOLENOID AND CHECK THE VALVE BODY
Replace the Governor Pressure Solenoid per with the Service Information.(Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR - REMOVAL)
Start the engine.
Warm the transmission to a normal operating temperature above 43° C (110° F).
CAUTION: Firmly apply the brakes.
With the engine RPM at idle, place the gear selector in Drive.
Read the governor pressure on the pressure gauge.
Is the governor pressure on the pressure gauge above 41.4 kPa (6 psi) with the engine RPM at idle and
9.CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN INSIDE THE TRANSMISSION
Reconnect the Transmission Solenoid Assembly harness connector.
Remove the transmission oil pan per the Service Information. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID -
STANDARD PROCEDURE)
Disconnect the Governor Pressure Sensor connector internal to the
transmission.
Measure the resistance of the 5-volt Supply circuit between the ECM
C2 harness connector and the Transmission Solenoid Assembly con-
nector internal to the transmission.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 10
No>>
Repair or replace the 5-volt Supply circuit for an open inter-
nal to the transmission.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
10.CHECK THE ENGINE CONTROL MODULE - 5 VOLT SUPPLY
Reconnect the ECM harness connectors.
Ignition on, engine not running.
Measure the voltage of the 5-volt Supply circuit in the Governor Pres-
sure Sensor connector internal to the transmission.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Replace the Governor Pressure Sensor per the Service
Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Using the schematics as a guide, check the Engine Control
Module (ECM) pins, terminals, and connectors for corrosion,
damage, or terminal push out. Pay particular attention to all
power and ground circuits. If no problems are found,
replace and program the ECM per the Service Information.
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
P1762-GOV PRESS SENSOR OFFSET VOLTS TOO LOW OR HIGH (DIESEL)
For a complete wiring diagramRefer to Section 8W
Theory of Operation
The Governor Pressure Sensors output is used as a control input to the Governor Pressure Control System. The
Governor Pressure Control System is used to regulate the governor pressure which controls the shifts for first, sec-
ond, and third gear.
When Monitored:
While the engine is running and the vehicle gear selector is in park or neutral for more than 3.0 seconds with
the throttle position less than 10%.
Set Condition:
This DTC will set if the Governor Pressure is greater than 3 psi while the vehicle is in Park 3 times in a drive
cycle.
Possible Causes
OTHER TRANSMISSION DTCS PRESENT
5 VOLT SUPPLY CIRCUIT OPEN - EXTERNAL
5 VOLT SUPPLY CIRCUIT OPEN - INTERNAL
GOVERNOR PRESSURE SENSOR
TRANSMISSION - INTERNAL DAMAGE
TRANSMISSION - INTERNAL LEAK
ENGINE CONTROL MODULE
INTERMITTENT WIRING AND CONNECTORS
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.OTHER TRANSMISSION DTCS PRESENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Are any other transmission DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom(s).
No>>
Go To 2
2.CHECK IF THE GOVERNOR PRESSURE IS ABOVE 21 KPA (3 PSI) IN PARK
CAUTION: Apply the parking brake.
Start the engine and allow the engine to idle.
Warm the transmission to a normal operating temperature above 43° C (110° F).
With the scan tool in Sensors, read the Governor Pressure with the Transmission Shift selector in Park.
Is the Governor Pressure reading on the scan tool above 21 kPa or 3 psi?
Ye s>>
Go To 3
No>>
Go To 10
cuits. If no problems are found, replace and program the ECM per the ServiceInformation. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 10
7.CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the ECM C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector.
NOTE: Check connectors - Clean/repair as necessary
Measure the resistance of the 5-volt Supply circuit between the Trans-
mission Solenoid Assembly harness connector and the ECM C2 har-
ness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair 5-volt Supply circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
8.CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN - INTERNAL
Reconnect the Transmission Solenoid Assembly harness connector.
Remove the Transmission Oil Pan perthe Service Information. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID -
STANDARD PROCEDURE)
Disconnect the Governor Pressure Sensor harness connector internal to
the transmission.
NOTE: Check connectors - Clean/repair as necessary
Measure the resistance of the 5-volt Supply circuit between the ECM
C2 harness connector and the Governor Pressure Sensor connector
internal to the transmission.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 9
No>>
Repair or replace the 5-volt Supply circuit for an open inter-
nal to the transmission.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
9.GOVERNOR PRESSURE SENSOR
Reconnect the ECM harness connectors.
NOTE: The ECM harness connectors must be connected during
this test.
Ignition on, engine not running.
Measure the voltage of the 5-volt Supply circuit at the Governor Pres-
sure Sensor connector internal to the transmission.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Replace the Governor Pressure Sensor per the Service
Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Using the schematics as a guide, check the Engine Control Module (ECM) pins, terminals, and connec-
tors for corrosion, damage, or terminal push out. Pay particular attentiontoallpowerandgroundcir-
cuits. If no problems are found, replace and program the ECM per the ServiceInformation. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
10.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention
to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched,
or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken,bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
CLEANING ................................. 1389
INSPECTION ............................... 1389
ASSEMBLY . ............................... 1390
INSTALLATION ............................. 1400
RETAINER-OVERRUNNING CLUTCH CAM/
OVERDRIVE PISTON
DESCRIPTION ............................. 1402
OPERATION ............................... 1402
DISASSEMBLY ............................. 1402
CLEANING ................................. 1403
INSPECTION ............................... 1403
ASSEMBLY . ............................... 1403
SHAFT-PLANETARY GEARTRAIN/OUTPUT
DESCRIPTION ............................. 1407
OPERATION ............................... 1407
DISASSEMBLY ............................. 1407
INSPECTION ............................... 1410
ASSEMBLY ................................ 1410
CLUTCH-REAR
DESCRIPTION ............................. 1416
OPERATION ............................... 1416
DISASSEMBLY ............................. 1417
CLEANING ................................. 1417
INSPECTION ............................... 1418
ASSEMBLY ................................ 1418
SERVO-REAR
DESCRIPTION ............................. 1421
OPERATION ............................... 1421
DISASSEMBLY ............................. 1421
CLEANING ................................. 1421
ASSEMBLY ................................ 1421
MECHANISM-SHIFT
DESCRIPTION ............................. 1422
OPERATION ............................... 1422
SENSOR-SPEED
DESCRIPTION ............................. 1423
OPERATION ............................... 1423
ACTUATOR-THROTTLE VALVE
DESCRIPTION ............................. 1424
REMOVAL ................................. 1424
INSTALLATION ............................. 1425
ADJUSTMENTS
ADJUSTMENT ............................ 1426
CABLE-THROTTLE VALVE
DESCRIPTION ............................. 1427ADJUSTMENTS - THROTTLE VALVE CABLE . . 1428
CONVERTER-TORQUE
DESCRIPTION ............................. 1431
OPERATION ............................... 1435
REMOVAL ................................. 1436
INSTALLATION ............................. 1437
VALVE-TORQUE CONVERTER DRAINBACK
DESCRIPTION
GAS ENGINES ........................... 1438
DIESEL ENGINE .......................... 1438
OPERATION
GAS ENGINES ........................... 1438
DIESEL ENGINE .......................... 1438
STANDARD PROCEDURE
GAS ENGINES ........................... 1438
DIESEL ENGINE .......................... 1438
SWITCH-TOW/HAUL OVERDRIVE
DESCRIPTION ............................. 1440
OPERATION ............................... 1440
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS ................. 1440
REMOVAL ................................. 1440
INSTALLATION ............................. 1441
SENSOR-TRANSMISSION RANGE
DESCRIPTION ............................. 1442
OPERATION ............................... 1442
DIAGNOSIS AND TESTING - TRANSMISSION
RANGE SENSOR (TRS) ................... 1443
REMOVAL ................................. 1444
INSTALLATION ............................. 1445
SENSOR-TRANSMISSION TEMPERATURE
DESCRIPTION ............................. 1447
OPERATION ............................... 1447
BODY-VALVE
DESCRIPTION ............................. 1448
OPERATION ............................... 1451
REMOVAL ................................. 1471
DISASSEMBLY ............................. 1472
CLEANING ................................. 1485
INSPECTION ............................... 1485
ASSEMBLY................................ 1486
INSTALLATION ............................. 1497
ADJUSTMENTS - VALVE BODY .............. 1498