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 .
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 rises above a predetermined value.
Possible Causes
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO ANOTHER CIRCUIT
(K900) SENSOR GROUND CIRCUIT OPEN
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 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 7
2.CHECK THE TTVA
With the scan tool, record and erase Engine DTCs.
Turn the ignition off to the lock position.
Disconnect the TTVA harness connector.
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Did the DTC Transmission Throttle Valve Position Sensor Circuit High set?
Ye s>>
Go To 4
No>>
Go To 3
3.CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN
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 (K900) Sensor Ground circuit and
the (F856) 5-volt Supply circuit in the TTVA harness connector.
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Did either P0642 or P0652 Sensor Supply Voltage DTC 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>>
Repair the (K900) TTVA Sensor Ground circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
4.CHECK THE (K312) TTVA POSITION SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
Turn the ignition off to the lock position.
Disconnect the ECM C1 and C2 harness connectors.
Ignition on, engine not running.
Measure the voltage of the (K312) TTVA Position Sensor Signal circuit.
Is the voltage above 0.5 volts?
Ye s>>
Repair the (K312) TTVA Position Sensor Signal circuit for a
short to voltage.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 5
5.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 6
6.CHECK THE ECM OPERATION
Turn the ignition off to the lock position.
Reconnect all previously disconnected connectors.
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.
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Did the DTC Transmission Throttle Valve Position Sensor Circuit High set?
Ye s>>
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)
No>>
Go To 7
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 .
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. After completion of the autozero procedure, the TTVA is instructed to
perform a span check to record the minimum and maximum span positions. ThisDTC will set if the minimum
total span is not achieved.
Possible Causes
TRANSMISSION THROTTLE VALVE ACTUATOR BINDING
TRANSMISSION THROTTLE VALVE
INTERNAL TRANSMISSION
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.
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 .