Page 3673 of 5267

3.CHECK THE (T38) GOVERNOR PRESSURESENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid Assembly harness connector.
Disconnect the ECM C1 and C2 harness connectors.
Measure the resistance between Ground and the (T38) Governor Pres-
sure Sensor Signal circuit in the Transmission Solenoid Assembly har-
ness connector.
Is the resistance greater than 100k ohms?
Ye s>>
Go To 4
No>>
Repair the (T38) Governor Pressure Sensor Signal circuit
for a short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
4.CHECK THE (T38) GOVERNOR PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO ANOTHER
CIRCUIT
Measure the resistance between the (T38) Governor Pressure Sensor
Signal circuit and all other circuits in the Transmission Solenoid Assem-
bly harness connector.
Is the resistance below 100k ohms between the (T38) Governor
Pressure Sensor Signal circuit and any other circuit(s) in the
Transmission Solenoid Assembly harness connector?
Ye s>>
Repair the (T38) Governor Pressure Sensor Signal circuit
for a short to another circuit(s).
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 5
Page 3674 of 5267

5.CHECK THE TRANSMISSION SOLENOID ASSEMBLY
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/Transmission Temperature Sensor
connector (inside transmission).
Measure the resistance between the (T38) Governor Pressure Sensor
Signal circuit and all other circuits in the ECM C1 and C2 harness con-
nectors.
Is the resistance below 100k ohms between the (T38) Governor
Pressure Sensor Signal circuit any other circuits in the ECM
C2 harness connector?
Ye s>>
Replace the Transmission Solenoid Assembly per the Ser-
vice Information.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 6
6.CHECK THE GOVERNOR PRESSURE SENSOR SENSOR
Turn the ignition on.
With the scan tool, erase DTCs.
Connect a jumper wire between the (T38) Governor Pressure Sensor
Signal circuit and the (F856) 5-volt Supply circuit in the Governor Pres-
sure Sensor connector.
With the scan tool, read DTCs.
Did the DTC P0868 set?
Ye s>>
Inspect the Governor Pressure Sensor wiring for damage. If
no problems are found, replace the Governor Pressure Sen-
sor per the Service Information.
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)
Page 3715 of 5267
P1749-TRANSMISSION THROTTLE VALVE POSITION SENSOR CIRCUIT LOW
For a complete wiring diagramRefer to Section 8W
Page 3716 of 5267

Theory of Operation
The transmission throttle valve cable has been replace by the transmission throttle valve actuator (TTVA). The TTVA
consists of an electric DC motor, two potentiometers, and a gear drive system. The TTVA is mechanically connected
to the transmission throttle valve in the valve body by the “D” shaped opening in the bottom of the TTVA shaft.
The Transmission Throttle Valve Actuator (TTVA) does not require any mechanical adjustments. All changes in throt-
tle valve position are controlled by the Engine Control Module (ECM).
The TTVA does require an initialization period after the actuator has beenremoved or replaced. After the actuator
has been removed or replaced, move the ignition to the ON position for thirty (30) seconds. This will allow the ECM
sufficient time to perform the internal calibration procedures to learn the TTVA’s current “zero” position.
When Monitored:
Continuously with the ignition on.
Set Condition:
When the Engine Control Module (ECM) detects the monitored Transmission Throttle Valve Position Sensor
voltage drops below a predetermined value.
Possible Causes
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT OPEN
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO GROUND
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO ANOTHER CIRCUIT
(F856) 5 VOLT SUPPLY CIRCUIT OPEN
(F856) 5 VOLT SUPPLY CIRCUIT SHORT TO GROUND
(F856) 5 VOLT SUPPLY CIRCUIT SHORT TO ANOTHER CIRCUIT
TRANSMISSION THROTTLE VALVE ACTUATOR
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 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.
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>>
Replace the TTVA per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 2
Page 3717 of 5267

2.CHECK THE (K312) TTVA POSITION SENSOR SIGNAL CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the ECM C1 and C2 harness connectors.
Measure the resistance of the (K312) TTVA Position Sensor Signal cir-
cuit between the ECM C1 harness connector and the TTVA harness
connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 3
No>>
Repair the (K312) TTVA Position Sensor Signal circuit for
an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
3.CHECK THE (K312) TTVA POSITION SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (K312) TTVA Position
Sensor Signal circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (K312) TTVA Position Sensor Signal circuit for a
short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 4
Page 3718 of 5267

4.CHECK THE (K312) TTVA POSITION SENSOR SIGNAL CIRCUIT FOR A SHORT TO ANOTHERCIRCUIT
Measure the resistance between the (K312) TTVA Position Sensor Sig-
nal circuit and all other circuits in the ECM C1 and C2 harness connec-
tors.
Is the resistance below 100 kohms between the (K312) TTVA
Position Sensor Signal circuit and any other circuit(s) in the
ECM C1 or C2 harness connectors.
Ye s>>
Repair the (K312) TTVA Position Sensor Signal circuit for a
short to another circuit(s).
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 5
5.CHECK THE (F856) 5 VOLT SUPPLY CIRCUIT FOR AN OPEN
Measure the resistance of the (F856) 5-volt Supply circuit between the
ECM C2 harness connector and the TTVA harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 6
No>>
Repair the (F856) 5-volt Supply circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
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