Page 3706 of 5267
P128E-TCM POWER CONTROL CIRCUIT 2 OVERCURRENT - TIPM
For a complete wiring diagramRefer to Section 8W.
Page 3709 of 5267
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
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 3710 of 5267

P1740-TCC O/D SOL PERFORMANCE (DIESEL)
For a complete wiring diagramRefer to Section 8W
Theory of Operation
The Torque Converter Clutch (TCC) Solenoid is used to engage the TCC which improves fuel economy.
When Monitored:
The Torque Convertor Clutch (TCC) and Overdrive Clutch (O/D) will be tested each time the ECM requests
TCC engagement in 3rd gear and O/D.
Set Condition:
The DTC will set if the expected RPM drop is not achieved while attempting toengage TCC or O/D. This
indicates a malfunctioning torqueconvertor or overdrive clutch.
Possible Causes
ENGINE DTCS PRESENT
TRANSMISSION DTCS PRESENT
TRANSMISSION TEMPERATURE TOO COLD
OIL PAN CONTAINS EXCESSIVE DEBRIS
3-4 SHIFT SOLENOID
SHAFT OR SEAL DAMAGE
TCC SOLENOID
TORQUE CONVERTER
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.ENGINE DTCS PRESENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Are there any Engine Temperature, Cam, Engine RPM, Misfire, P/N, or TPS DTC’s present?
Ye s>>
Refer to 9 - ENGINE ELECTRICAL DIAGNOSTICS - DIESEL and perform the appropriate symptom.
No>>
Go To 2
2.CHECK FOR OTHER TRANSMISSION DTCS PRESENT
Are any of the DTCs P0720, P0973, P0974, P2769, and/or P2770, also present?
Ye s>>
Refer to the Transmission category, and perform the appropriate symptom(s).
No>>
Go To 3
Page 3714 of 5267
14.INTERMITTENT WIRING & 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 3715 of 5267
P1749-TRANSMISSION THROTTLE VALVE POSITION SENSOR CIRCUIT LOW
For a complete wiring diagramRefer to Section 8W
Page 3720 of 5267

8.CHECK THE TTVA
Ignition on, engine not running.
With the scan tool, record and erase Engine DTCs.
Turn the ignition off to the lock position.
Disconnect the TTVA harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Connect a jumper wire between the (K312) TTVA Position Sensor Sig-
nal circuit and the (F856) 5-volt Supply circuit in the TTVA harness con-
nector.
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Did the DTC P1750-Transmission Throttle Valve Position Sensor
Circuit High set?
Ye s>>
Go To 9
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)
9.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions that set the DTC.Pay particular attention to the DTC
set conditions, such as, VSS, MAP, ECT, and Load.
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.
Refer to any 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 3721 of 5267
P1750-TRANSMISSION THROTTLE VALVE POSITION SENSOR CIRCUIT HIGH
For a complete wiring diagramRefer to Section 8W
Page 3725 of 5267
7.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions that set the DTC.Pay particular attention to the DTC
set conditions, such as, VSS, MAP, ECT, and Load.
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.
Refer to any 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 .