For a complete wiring diagramRefer to Section 8W
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:
Ignition on and with or without engine running with transmission in the park or neutral position. Note: Not mon-
itored when either the engine is cranking or while vehicle is moving.
Set Condition:
Each time the ignition is cycled to the on position, the ECM commands a TTVA internal calibration procedure
(autozero) to determine the zero position. If the TTVA does not reach a calibrated minimum position in a pre-
determined amount of time, the DTC will set.
Possible Causes
TRANSMISSION THROTTLE VALVE ACTUATOR BINDING
TRANSMISSION THROTTLE VALVE COMPONENTS
TRANSMISSION THROTTLE VALVE ACTUATOR
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 5
2.CHECK TTVA FOR SIGNS OF DAMAGE
Turn the ignition off to the lock position.
Visually inspect the TTVA shaft for any signs of external damage or improperly mounted.
NOTE: It is not necessary to remove the TTVA to perform this procedure.
Is the TTVA damaged or improperly mounted?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 3
3.CHECK THE TTVA POSITIONS WITH THE AUTO ZERO FEATURE
NOTE: Each time the ignition is cycled to the on position, the ECM commands aTTVA internal calibration
procedure (autozero) to determine the zero position. Do not press on the accelerator pedal during this test.
With the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
Is the TTVA position between 3 and 26 degrees after completion of the autozero test?
Ye s>>
Go To 5
No>>
Go To 4
4.CHECK THE TRANSMISSION THROTTLE VALVE
Turn the ignition off to the lock position.
Remove the TTVA from the transmission per the Service Information.
Properly support the TTVA and reconnect the TTVA wiring harness.
Like in the previous step, with the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
Is the TTVA position between 3 and 22 degrees after completion of the autozero test?
Ye s>>
Repair internal transmission as necessary. Refer to the Service Information for proper repair procedures
for components related to the Transmission Throttle Valve.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Replace the TTVA per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
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 .
P1752-TRANSMISSION THROTTLE VALVE SPAN PERFORMANCE
For a complete wiring diagramRefer to Section 8W
3.CHECK THE TTVA POSITIONS WITH THE AUTO ZERO FEATURE
NOTE: Each time the ignition is cycled to the on position, the ECM commands aTTVA internal calibration
procedure (autozero) to determine the zero position.
With the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
After the autozero test is completed, record the position percentage value.
Press and hold the accelerator pedal to full throttle after completion of the autozero test and record.
After completion of the autozero test and recording the autozero value, press and hold the accelerator pedal to full
throttle and record the autozero value on the scan tool.
Subtract the TTVA full throttle value from the value recorded after the autozero test.
Is the difference between the two values greater than or equal to 48 degrees?
Ye s>>
Go To 5
No>>
Go To 4
4.CHECK THE TRANSMISSION THROTTLE VALVE
Turn the ignition off to the lock position.
Remove the TTVA from the transmission per the Service Information.
Properly support the TTVA and reconnect the TTVA wiring harness.
Like in the previous step, with the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
After the autozero test is completed, record the position percentage value.
Press and hold the accelerator pedal to full throttle after completion of the autozero test and record.
After completion of the autozero test and recording the autozero value, press and hold the accelerator pedal to full
throttle and record the autozero value on the scan tool.
Subtract the TTVA full throttle value from the value recorded after the autozero test.
Is the difference between the two values greater than or equal to 51 degrees?
Ye s>>
Repair internal transmission as necessary. Refer to the Service Information for proper repair procedures
for components related to the Transmission Throttle Valve.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Replace the TTVA per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
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 .
P1753-TRANSMISSION THROTTLE VALVE MECHANICAL PERFORMANCE
For a complete wiring diagramRefer to Section 8W
3.CHECK IF TTVA SHAFT END IS DAMAGED
Turn the ignition off to the lock position.
Remove the TTVA from the transmission per the Service Information. (Referto 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE/THROTTLE VALVE ACTUATOR - REMOVAL)
Inspect the end of the TTVA shaft for cracks or damage.
NOTE: The end of the TTVA should be keyed or ”D” shaped and fit tightly over the Throttle Valve shaft.
Is the end of the TTVA shaft undamaged and fit tightly over the Throttle Valveshaft?
Ye s>>
Go To 4
No>>
Inspect the Throttle Valve shaft on the transmission for free movement. Ifthe Throttle valve does not
move freely, inspect internal transmission components related to the Throttle Valve and replace as nec-
essary. Replace the TTVA in either case. Refer to the Service Information.(Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE/THROTTLE VALVE ACTUATOR - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
4.CHECK THE TRANSMISSION THROTTLE VALVE ACTUATOR
Properly support the TTVA to where the end of the shaft can be observed and reconnect the TTVA wiring harness.
NOTE: Each time the ignition is cycled to the on position, the ECM commands aTTVA internal calibration
procedure (autozero) to determine the zero position. Do not press on the accelerator pedal during this test.
Ignition on, engine not running.
Observe the output shaft of the TTVA during the autozero procedure.
After completion of the autozero procedure, while observing the TTVA shaft, press the accelerator pedal to full throt-
tle.
Does the TTVA internal motor move the TTVA shaft?
Ye s>>
Inspect the Throttle Valve shaft on the transmission for free movement. Ifthe Throttle valve does not
move freely, inspect internal transmission components related to the Throttle Valve and repair or replace
as necessary. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 48RE/THROTTLE VALVE
ACTUATOR - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Replace the TTVA per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
5.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
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 .
P1754-TRANSMISSION THROTTLE VALVE ACTUATOR STUCK
For a complete wiring diagramRefer to Section 8W
2.CHECK THE TTVA POSITIONS WITH THE AUTO ZERO FEATURE
NOTE: Each time the ignition is cycled to the on position, the ECM commands aTTVA internal calibration
procedure (autozero) to determine the zero position.
With the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
After the autozero test is completed, record the position percentage value.
Press and hold the accelerator pedal to full throttle after completion of the autozero test and record.
Subtract the TTVA full throttle value from the value recorded after the autozero test.
Is the difference between the two values greater than or equal to 48 degrees?
Ye s>>
Go To 16
No>>
Go To 3
3.CHECK TTVA FOR SIGNS OF DAMAGE
Turn the ignition off to the lock position.
Visually inspect the TTVA shaft for any signs of external damage or improperly mounted.
NOTE: It is not necessary to remove the TTVA to perform this procedure.
Is the TTVA damaged or improperly mounted?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 4
4.CHECK THE TTVA POSITIONS WITH THE TTVA REMOVED
Turn the ignition off to the lock position.
Remove the TTVA from the transmission per the Service Information. (Referto 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE/THROTTLE VALVE ACTUATOR - REMOVAL)
NOTE: Check connectors - Clean/repair as necessary.
NOTE: Each time the ignition is cycled to the on position, the ECM commands aTTVA internal calibration
procedure (autozero) to determine the zero position.
Properly support the TTVA and reconnect the TTVA wiring harness.
With the scan tool, monitor the TTVA position during the autozero test.
Ignition on, engine not running.
After the autozero test is completed, record the position percentage value.
After recording the position percentage value, press and hold the accelerator pedal to full throttle and note position
percentage value.
Subtract the TTVA full throttle value from the value recorded after the autozero test.
Is the difference between the two values greater than or equal to 48 degrees?
Ye s>>
Repair internal transmission as necessary. Refer to the Service Information for proper repair procedures
for components related to the Transmission Throttle Valve.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 5