Symptom:
P-0740 TORQUE CONV CLUTCH, NO RPM DROP AT LOCKUP
When Monitored and Set Condition:
P-0740 TORQUE CONV CLUTCH, NO RPM DROP AT LOCKUP
When Monitored: Continuously when no matured or maturing Trouble Code and throttle
position >10% and constant for 4.4 seconds before TCC engagement requested: No TCC
solenoid circuit, any cam/crank-related code, VSS, any TPS-related code and Battery
voltage >11.0
Set Condition: Torque Converter malfunctions that are detected are the FTC not locking
up properly when desired, and the torque converter not unlocking properly when desired.
3 consecutive test failures over one trip will store the code. 2 bad trips will set the code.
POSSIBLE CAUSES
FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
DIFF, SHAFT, OR GEARS DEFECTIVE
TCC SOL DEFECTIVE
TORQUE CONVERTER ASSEMBLY DEF OR TCC SOL STUCK
TRANSMISSION FLUID DIRTY OR LEVEL LOW
VEHICLE CONFIGURATION NON-STANDARD
TEST ACTION APPLICABILITY
1 Ignition On, Engine Not Running
With the DRB, read codes.
Is the Global Good Trip displayed and equal to 0?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 2
No®Test Complete.
2 Ignition Off
At the9Cooler In9port puta0to300PSIgauge using a9T9. Ensure line is long
enough to reach in driver's side of vehicle so gauge can be monitored while driving.
Road test vehicle. Gear select in drive. While monitoring DRB, achieve 50 MPH.
While doing this, notice the gauge will read around 15 PSI until lockup is achieved
in 3rd gear. If the TCC Solenoid is operating properly, the gauge pressure will
fluctuate when lockup is achieved.
Did gauge fluctuate?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 3
No®Refer to service instructions for proper service procedure on
Torque Converter Assembly or stuck TCC Solenoid and repair as
necessary.
Perform Powertrain Verification Test VER-5A.
302
TRANSMISSION
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TEST ACTION APPLICABILITY
3 Ignition Off
Check Transmission Fluid level and ensure it is clear of any debris.
Is the Transmission Fluid okay?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 4
No®Repair as necessary.
Perform Powertrain Verification Test VER-5A.
4 Ignition Off
Disconnect the TCC Solenoid connector.
Note: Check connectors - Clean/repair as necessary.
Turn key on.
Use a Voltmeter in the following step.
Using a Voltmeter, measure the Fused Ignition Switch Output Circuit at Solenoid
Connector.
Is the voltage above 10.0 volts?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 5
No®Repair the open Fused Ignition Switch Output Circuit.
Perform Powertrain Verification Test VER-5A.
5 Ignition Off
Disconnect the TCC Solenoid connector.
Note: Check connectors - Clean/repair as necessary.
With an Ohmmeter, measure across the Solenoid for resistance.
Was resistance between 30.0 and 50.0 ohms?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 6
No®Replace TCC Solenoid.
Perform Powertrain Verification Test VER-5A.
6 Drive Vehicle
Maintain 50 MPH per DRB. Wait 10 seconds in lockup. Record Engine RPM.
Was engine RPM 2200 +/- 50 RPM?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Go To 7
No®Inspect Differential, Output Shaft, or Gear Box. Refer to service
instructions for proper diagnosis.
Perform Powertrain Verification Test VER-5A.
7 Ignition Off
Remove VSS.
Note: Check connectors - Clean/repair as necessary.
Inspect sensor and gear for damage, also improper wheel size.
Were any problems found?TRANSMISSION -
AUTOMATIC
3-SPD, 31TH
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
303
TRANSMISSION
P-0740 TORQUE CONV CLUTCH, NO RPM DROP AT LOCKUP ÐContinued
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