problems are found, replace and program the TIPM per the
Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 3
3.CHECK THE (T515) TRANSMISSION CONTROL CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the PCM C2 harness connector.
Connect a jumper wire between cavity 30 in the PCM C2 harness con-
nector and ground.
Using a 12-volt test light connected to 12 volts, check the (T515) Trans-
mission Control circuit at the TIPM C1 harness connector.
Does the test light illuminate brightly?
Ye s>>
Go To 4
No>>
Repair the (T515) Transmission Control circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (GAS). (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE - STANDARD PROCEDURE)
4.CHECK THE (T515) TRANSMISSION CONTROL OUTPUT CONTROL CIRCUIT SHORT TO GROUND
Turn the ignition off to the lock position.
Disconnect the TIPM C1 harness connector.
Remove the jumper wire from the PCM C2 harness connector.
Ignition on, engine not running.
Measure the resistance between ground and the (T515) Transmission Control circuit at the TIPM C1 harness con-
nector.
Is the resistance above 100k ohms?
Ye s>>
Repair the (T515) Transmission Control circuit for a short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 5
5.CHECK THE (T515) TRANSMISSION CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the TIPM C1 harness connector.
Disconnect the PCM C2 harness connector.
Ignition on, engine not running.
Using a volt meter connected to ground, check the (T515) Transmission
Control circuit at the TIPM C1 harness connector.
Is the voltage above 1.0 volts?
Ye s>>
Repair the (T515) Transmission Control circuit for a short to
voltage.
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 Engine 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 MOD-
ULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (GAS). (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 (GAS). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
STANDARD PROCEDURE
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 page
AUTOMATIC TRANSMISSION - 48RE - DIESEL -
ELECTRICAL DIAGNOSTICS
DIAGNOSIS AND TESTING
P0711-TRANS TEMP SENSOR, NO TEMP
RISE AFTER START (DIESEL).............. 1107
P0712-TRANS TEMP SENSOR VOLTAGE
TOO LOW (DIESEL).......................1111
P0713-TRANS TEMP SENSOR VOLTAGE
TOO HIGH................................ 1117
P0720-LOW OUTPUT SPEED SENSOR -
RPM ABOVE 15 MPH (DIESEL)............ 1125
P0748-PRESSURE SOL CONTROL/TRANS
RELAY CIRCUITS (DIESEL)................ 1131
P0850-P/N SWITCH PERFORMANCE
(DIESEL)................................. 1138
P0868-GOVERNOR PRESSURE SENSOR
VOLTS TOO HI (DIESEL).................. 1143
P0869-GOVERNOR PRESSURE SENSOR
VOLTS TOO LOW (DIESEL)................ 1150
P0882-TRANS 12 VOLT SUPPLY RELAY
CONTROL CIRCUIT LOW (DIESEL)......... 1155
P0883-TRANS 12 VOLT SUPPLY RELAY
CONTROL CIRCUIT HIGH (DIESEL)........ 1159
P0973-TRANSMISSION OVERDRIVE
CIRCUIT VOLTAGE TOO LOW (DIESEL).... 1163
P0974-TRANSMISSION OVERDRIVE
CIRCUIT VOLTAGE TOO HIGH (DIESEL).... 1171
P128B-TCM POWER CONTROL CIRCUIT 2
LOW - TIPM.............................. 1176
P128C-TCM POWER CONTROL CIRCUIT 2
HIGH - TIPM.............................. 1179
P128D-TCM POWER CONTROL CIRCUIT 2
OPEN - TIPM............................. 1182
P128E-TCM POWER CONTROL CIRCUIT 2
OVERCURRENT - TIPM................... 1185P1740-TCC O/D SOL PERFORMANCE
(DIESEL)................................. 1189
P1749-TRANSMISSION THROTTLE VALVE
POSITION SENSOR CIRCUIT LOW......... 1194
P1750-TRANSMISSION THROTTLE VALVE
POSITION SENSOR CIRCUIT HIGH........ 1200
P1751-TRANSMISSION THROTTLE VALVE
POSITION MINIMUM RANGE
PERFORMANCE.......................... 1205
P1752-TRANSMISSION THROTTLE VALVE
SPAN PERFORMANCE.................... 1208
P1753-TRANSMISSION THROTTLE VALVE
MECHANICAL PERFORMANCE............ 1211
P1754-TRANSMISSION THROTTLE VALVE
ACTUATOR STUCK....................... 1214
P1755-TRANSMISSION THROTTLE VALVE
CONTROL CIRCUIT....................... 1223
P1756-GOV PRESS NOT EQUAL TO
TARGET @ 35 - 40 PSI (DIESEL)........... 1231
P1757-GOV PRESS ABOVE 3 PSI IN GEAR
WITH 0 MPH (DIESEL).................... 1238
P1762-GOV PRESS SENSOR OFFSET
VOLTS TOO LOW OR HIGH (DIESEL)...... 1244
P2769-TRANSMISSION TCC CONTROL
CIRCUIT LOW............................ 1249
P2770-TRANSMISSION TCC CONTROL
CIRCUIT HIGH (DIESEL).................. 1256
*TOW /HAUL OVERDRIVE OFF SWITCH
(DIESEL)................................. 1261
STANDARD PROCEDURE
TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL)............................... 1264
PRE-DIAGNOSTIC CHECKOUT (DIESEL) . . . 1265
AUTOMATIC TRANSMISSION - 48RE - DIESEL - ELECTRICAL
DIAGNOSTICS
DIAGNOSIS AND TESTING
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). (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 48RE - DIAGNOSIS AND TESTING)
No>>
Go To 3
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 .
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
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.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