11 .CHECK THE POWERTRAIN CONTROL MODULE
Reconnect all disconnected connectors.
Ignition on, engine not running.
With the scan tool, erase Engine DTCs.
Turn the ignition off to the lock position.
Disconnect the Governor Pressure Sensor connector internal to the
transmission.
Connect a jumper wire between the (T54) Transmission Temperature
Sensor Signal circuit and the (K900) Sensor Ground circuit in the Trans-
mission Solenoid Assembly harness connector.
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Did the DTC Transmission Oil Temperature Sensor Voltage Too
Low set?
Ye s>>
Go To 12
No>>
Using the schematics as a guide, check the Powertrain
Control Module (PCM) 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 PCM per the Service
Information. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL MODULE
- REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
12.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 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
4.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 5
No>>
Go To 9
5.PERFORM TCC SYSTEM TEST
With the scan tool, perform the TCC System Test.
Follow the instructions on the screen.
Did the engine stall?
Ye s>>
Go To 6
No>>
Go To 7
6.PERFORM GOV AND 3-4 SHIFT VALVE SYSTEM TEST
With the scan tool, perform the Gov and 3-4 Shift Valve System Test.
Follow the instructions on the screen.
Did the engine stall?
Ye s>>
Go To 8
No>>
Go To 7
7.CHECK THE COOLER OUT PRESSURE
Turn the ignition off to the lock position.
Connect a pressure gauge to the transmission cooler out port with a “T” connector. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
Start the engine, with the scan tool, perform the TCC System Test.
Did the cooler out pressure on the gauge increase when the TCC was actuated?
Ye s>>
Remove the transmission oil pump and inspect the reaction shaft, input shaft and input shaft seals for
damage or wear and repair or replace as necessary. Replace the Torque Convertor.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Remove the Valve Body and inspect for an internal blockage or an internal leak in the TCC hydraulic
circuit. Repair as necessary. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO M AT I C - 4 8 R E / VA LV E
BODY - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
7.CHECK THE (T118) GOVERNOR PRESSURE SOLENOID CONTROL CIRCUIT FOR A SHORT TO
ANOTHER CIRCUIT
Turn the ignition off to the lock position.
Remove the Transmission Control Relay.
Measure the resistance between the (T118) Governor Pressure Sole-
noid Control circuit and all other circuits in the Transmission Solenoid
Assembly harness connector.
Is the resistance below 5.0 ohms between the (T118) Governor
Pressure Solenoid Control circuit and any other circuit in the
Transmission Solenoid Assembly harness connector?
Ye s>>
Repair the (T118) Governor Pressure Solenoid Control cir-
cuit for a short to another circuit(s).
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (GAS). (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 8
8.CHECK THE GOVERNOR PRESSURE SOLENOID
Remove the Transmission Oil Pan per the Service Information. (Refer to 21 -TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE/FLUID - STANDARD PROCEDURE)
Check all internal wiring pertaining to the Governor Pressure Solenoid for an open, short, and bent or broken ter-
minals.
If no internal wiring problems are found, replace the Governor Pressure Solenoid per the Service Information. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR - REMOVAL)
Drive the vehicle performing multiple upshifts and downshifts.
With the scan tool, read Transmission DTCs.
Does the DTC reset?
Ye s>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)pins, terminals, and con-
nectors 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 PCM per the Service Information. (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/POWERTRAIN CONTROL MODULE -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
NOTE: The governor pressure should rise above 138 kPa (20 PSI). Shortly after the O/D pressure should
rise above 276 kPa (40 PSI).
Did the pressures act as previously described?
Ye s>>
Go To 4
No>>
Go To 5
4.CHECK THE TRANSMISSION OIL CONDITION
Turn the ignition off to the lock position.
Remove the transmission oil pan and inspect for excessive debris and burntoil.
Is the oil burnt or does the transmission oil pan contain excessive debris?
Ye s>>
Repair the transmission as necessary. Refer to the Service Informtion forthe proper repair procedures.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 6
5.CHECK THE GOVERNOR AND OVERDRIVE PRESSURE AFTER REPLACEMENT OF THE 3-4 SHIFT
SOLENOID
Turn the ignition off to the lock position.
Replace the 3-4 Shift Solenoid per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 48RE/VALVE BODY - DISASSEMBLY)
With the pressure gauges still attached, start the engine and allow the transmission temperature to rise to normal
operating temperature.
CAUTION: Apply the parking brake.
Firmly apply the brakesand place the gear selector in Drive.
While observing the pressure gauges, with the scan tool, select 4th gear from the Gov and 3-4 Shift Valve Test.
NOTE: The governor pressure should rise to above 138 kPa (20 PSI). Shortly after the O/D pressure should
rise above 276 kPa (40 PSI).
Did the pressures act as previously described?
Ye s>>
Te s t C o m p l e t e .
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Overhaul the transmission per the Service Information. Pay attention to seals and clutches related to the
OD clutch.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
7.GOVERNOR PRESSURE SYSTEM TEST
Turn the ignition off to the lock position.
Connect a 0 to 2068 kPa or 0 to 300 PSI pressure gauge to the Overdrive Clutch Test Port.
Connect a 0 to 2068 kPa or 0 to 300 PSI pressure gauge to the Governor Test Port.
Start the engine.
NOTE: Allow the transmission temperature to rise to normal operating temperature.
While observing both pressure gauges, select 4th Gear from Gov and 3-4 System Test.
NOTE: The Governor pressure should rise to above 137.8 kPa or 20 PSI, shortly after the OD pressure
should rise above 275.7 kPa or 40 PSI.
Did the pressures act as described?
Ye s>>
Go To 8
No>>
Go To 9
8.CHECK IF THE OIL PAN CONTAINS EXCESSIVE DEBRIS
Remove the transmission oil pan per the Service information.
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 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 10
9.CHECK THE 3-4 SHIFT SOLENOID
Turn the ignition off to the lock position.
Replace the 3-4 Solenoid per the Service information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC -
4 8 R E / VA LV E B O D Y - R E M O VA L )
Connect a 0 to 2068 kPa or 0 to 300 PSI pressure gauge to the Overdrive Clutch Test Port.
Connect a 0 to 2068 kPa or 0 to 300 PSI pressure gauge to the Governor Test Port.
Start the engine.
NOTE: Allow the transmission temperature to rise to normal operating temperature.
While observing both pressure gauges, select 4th gear from the Governor 3-4 shift valve system test.
NOTE: The Governor pressure should rise above 137.8 kPa or 20 PSI, shortly after the OD pressure should
rise above 275.7 kPa or 40 PSI.
Did the pressures act as described?
Ye s>>
Te s t C o m p l e t e .
No>>
Overhaul the transmission per the Service Information. Carefully inspect the seals and clutches related
to the OD Clutch. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE -REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
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 driving and the commanded governor pressure is equal to the pressurerequired for third gear.
Set Condition:
If the governor pressure sensor output is less than 407 kPa (60 psi) or greater than 621 kPa (80 psi) when the
requested pressure is 407 - 621 kPa (60 - 80 psi) for 2.2 seconds. This DTC will set if there are two trips of
five consecutive bad 2.2 second tests with the transmission oil temperature between 23.5 - 88° C (74 - 190°
F).
Possible Causes
OTHER TRANSMISSION DTCS PRESENT
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT OPEN - INTERNAL
GOVERNOR PRESSURE SENSOR
VA LV E B O D Y
INTERNAL TRANSMISSION
POWERTRAIN CONTROL MODULE
TRANSMISSION - INTERNAL DAMAGE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.CHECK IF OTHER TRANSMISSION DTCS ARE 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). (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.CHECK IF THE GOVERNOR PRESSURE IS ABOVE 3 PSI IN DRIVE
CAUTION: Apply the parking brake.
Start the engine and allow the transmission to reach normal operating temperature above 43° C (110° F).
CAUTION: Apply the brakes.
With the engine at idle, place the gear selector in Drive.
With the scan tool, read the Governor Pressure.
Is the Governor Pressure above 21 kPa (3 psi)?
Ye s>>
Go To 3
No>>
Go To 4
8.CHECK THE 5 VOLT SUPPLY CIRCUIT FOR AN OPEN - INTERNAL
Remove the transmission oil pan. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE/FLUID - STANDARD PROCEDURE)
Reconnect the Transmission Solenoid Assembly harness connector.
Disconnect the Governor Pressure Sensor connector internal to the
transmission.
Measure the resistance of the 5-volt Supply circuit between the PCM
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 (GAS). (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE - STANDARD PROCEDURE)
9.GOVERNOR PRESSURE SENSOR
Reconnect the PCM harness connectors.
NOTE: The PCM harness connectors must not be disconnected
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/Transmission Temperature
Sensor per the Service Information. (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 48RE/GOVERNOR
PRESSURE SENSOR - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (GAS). (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)pins, terminals, and con-
nectors 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 PCM per the Service Information. (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/POWERTRAIN CONTROL MODULE -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
10.TRANSMISSION - INTERNAL DAMAGE
Turn the ignition off to the lock position.
Remove the transmission oil pan per the Service Information. (Refer to 21 -TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 48RE/FLUID - STANDARD PROCEDURE)
Inspect the transmission oil pan for burnt transmission fluid and/or excessive debris.
Is the transmission fluid burnt and/or contain excessive debris?
Ye s>>
Repair the internal transmission per the Service Information. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 48RE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 11
11 .CHECK THE VALVE BODY
Replace the Governor Pressure Solenoid per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE/GOVERNOR PRESSURE SENSOR - REMOVAL)
Install a pressure gauge at the governor pressure test port. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 48RE - DIAGNOSIS AND TESTING)
Start the engine.
Warm the transmission to normal operating temperature.
CAUTION: Apply the brakes.
Place the gear selector in Drive and allow the engine to idle.
Read the governor pressure on the pressure gauge in Drive.
Is the governor pressure on the gauge below 21 kPa (3 psi)?
Ye s>>
Go To 12
No>>
Repair or replace the Valve Body per the Service Information. (Refer to 21 -TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 48RE/VALVE BODY - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
12.VERIFY OPERATION - TEST DRIVE
Remove the pressure gauge from the transmission. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC -
48RE - DIAGNOSIS AND TESTING)
Test drive the vehicle.
Be sure to drive the vehicle at a constant speed of 40-48 Kmh or 25-30 MPH during the drive cycle.
With the scan tool, read Engine DTCs.
Did the DTC reset?
Ye s>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)pins, terminals, and con-
nectors 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 PCM per the Service Information. (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/POWERTRAIN CONTROL MODULE -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)