Page 3624 of 5267

PRE-DIAGNOSTIC TROUBLE SHOOTING PROCEDURE - 48RE GAS
For a complete wiring diagramRefer to Section 8W
1.
NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms.
NOTE: Low fluid level can be the cause of many transmission problems. If thefluid level is low locate and
repair the leak then check and adjust the fluid level per the Service Information.
With the scan tool, read engine DTC’s. Check and repair all engine DTCs prior to performing transmission symptom
diagnostics.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Verify the flash level of the Powertrain Control Module. Some problems arecorrected by software upgrades.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Did any of the above checks or procedures correct the symptom?
Ye s>>
Repair is complete.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Refer to the Transmission category and perform the appropriate symptom(s). (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
Page 3625 of 5267

TRANSMISSION VERIFICATION TEST VER - 1 (GAS)
1.
1. Inspect the vehicle to ensure that all engine and transmission components are properly installed and connected.
Reassemble and reconnect components as necessary.
2. If any existing diagnostic trouble codes have not been repaired, go to Symptom List and follow path specified.
3. Connect a scan tool to the data link connector.
4. Ensure the fuel tank has at least a quarter tank of fuel. Turn off all accessories.
5. Start and run the engine until the transmission temperature is above 43°C(110°F).
6. Check the transmission fluid level per the Service Information. Adjustif necessary.
7. Road test the vehicle. Make 15 to 20 1-2, 2-3 and 3-4 up shifts. Perform these shifts from a standing start to 72
km/h (45 MPH) with a constant throttle opening of 20-25%.
8. Below 40 km/h (25 MPH), make 5 to 8 wide open throttle kick downs to 1st gear. Allow at least 5 seconds each
in 2nd and 3rd between each kick down.
9. For a specific DTC, drive the vehicle in accordance with the Symptom’s When Monitored and Set Conditions to
verify the repair.
10. If a DTC sets during the road test, return to the Symptom List and follow the path. If no DTC sets, the repair is
complete.
Are there any DTCs or symptoms remaining?
Ye s>>
Repair is not complete, refer to appropriate symptom.
No>>
Repair is complete.
Page 3631 of 5267

Turn the ignition off to the lock position.
Remove the Transmission Oil Pan per the Service Information. (Refer to 21 -TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 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 Transmission Temperature Sensor between the (T54) Transmission Temperature Sen-
sor Signal circuit and the (K900) Sensor Ground circuit.
Using the chart at the chart above, compare the Temperature Sensor temperature to the correlating resistance
value.
Is the resistance within the specified range when the sensor is at the giventemperature?
Ye s>>
Te s t C o m p l e t e .
No>>
Replace the Governor Pressure/Transmission Temperature 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)
6.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 .
Page 3635 of 5267

4.CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORTTO
GROUND INSIDE TRANSMISSION
Remove the Transmission Oil Pan perthe Service Information. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/FLUID -
STANDARD PROCEDURE)
Disconnect the Governor Pressure Sensor connector interal to the
transmission.
Measure the resistance between ground and the (T54) Transmission
Temperature Sensor Signal circuit at the Governor Pressure Sensor
connector.
Is the resistance above 100k ohms?
Ye s>>
Go To 5
No>>
Replace the Transmission Solenoid Assembly per the Ser-
vice Information. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 48RE/VALVE BODY - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
5.CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (K900)
SENSOR GROUND CIRCUIT INSIDE TRANSMISSION
Measure the resistance between the (T54) Transmission Temperature
Sensor Signal circuit and (K900) Sensor Ground circuit at the Governor
Pressure Sensor connector.
Is the resistance above 100k ohms?
Ye s>>
Go To 6
No>>
Replace the Transmission Solenoid Assembly per the Ser-
vice Information. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 48RE/VALVE BODY - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
Page 3636 of 5267

6.TRANSMISSION TEMPERATURE SENSOR
TYPICAL VALUES FOR TRANSMISSION TEMPERATURE SENSOR
TEMPERATURE MIN TO MAX OHM RANGE
-40° C (-40° F) 1094 to 1176 ohms
0.0° C (32° F) 1587 to 1672 ohms
25° C (77° F) 1960 to 2040 ohms
70° C (158° F) 2709 to 2860 ohms
0° C (212° F) 3284 to 3500 ohms
120° C (120° F) 3684 to 3950 ohms
150° C (302° F) 4110 to 4450 ohms
Measure the resistance of the Transmission Temperature Sensor between the (T54) Transmission Temperature Sen-
sor Signal circuit and (K900) Sensor Ground circuit.
Using the chart above, compare the Temperature Sensor temperature to the correlating resistance value.
Is the resistance below the minimum specification for the sensor temperature?
Ye s>>
Replace the Governor Pressure/Transmission Temperature 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>>
Go To 7
7.ENGINE CONTROL MODULE
Reconnect the all disconnected connectors.
Ignition on, engine not running.
With the scan tool, erase Engine DTCs.
With the scan tool, monitor Engine DTC’s.
Disconnect the Transmission Temperature Sensor connector.
Did the DTC P0713 set?
Ye s>>
Go To 8
No>>
Replace and program the Engine Control Module per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Page 3637 of 5267
8.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 origionaly 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 .
Page 3644 of 5267

10.CHECK THE TRANSMISSION TEMPERATURE SENSOR
TYPICAL VALUES FOR TRANSMISSION TEMPERATURE SENSOR
TEMPERATURE MIN TO MAX OHM RANGE
-40° C (-40° F) 1094 to 1176 ohms
0.0° C (32° F) 1587 to 1672 ohms
25° C (77° F) 1960 to 2040 ohms
70° C (158° F) 2709 to 2860 ohms
0° C (212° F) 3284 to 3500 ohms
120° C (120° F) 3684 to 3950 ohms
150° C (302° F) 4110 to 4450 ohms
Measure the resistance of the Transmission Temperature Sensor between the (T54) Transmission Temperature Sen-
sor Signal circuit and the (K900) Sensor Ground circuit.
Using the chart above, compare the Temperature Sensor temperature to the correlating resistance value.
Is the Temperature Sensor resistance above the maximum specification listedinthechart?
Ye s>>
Replace the Governor Pressure/Transmission Temperature 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>>
Go To 11
Page 3645 of 5267

11 .CHECK THE ENGINE 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 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)
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 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .