P0740
DTC P0740 Torque Converter Clutch (TCC) Circuit (1 Of 4):
DTC P0740 Torque Converter Clutch (TCC) Circuit (2 Of 4):
DTC P0740 Torque Converter Clutch (TCC) Circuit (3 Of 4):
DTC P0740 Torque Converter Clutch (TCC) Circuit (4 Of 4):
Torque Converter Clutch (TCC) Circuit:
CIRCUIT DESCRIPTION
Based on signals from the Throttle Position (TP) sensor (throttle opening), the ignition coil and Engine Coolant Temperature (ECT) sensor, the Engine Control Module (ECM) will provide the ground for the Torque Converter Clutch (TCC) circuit. The TCC solenoid under control of the TCC relay, opens and closes the automatic transmission fluid passage to lock and unlock the TCC.
CONDITIONS FOR SETTING THE DTC
One of the following two sets of conditions are detected for 5 seconds continuously:
FIRST SET OF CONDITIONS:
- Transmission range switch "OFF" (R, D, 2, L range).
- Engine speed less than 3500 rpm.
- Throttle angle is between 12.2° and 40.0°.
- Engine coolant temperature above 60°C (140°F).
- Vehicle speed is above 75.4 km/h (47 mph).
- Vehicle speed to engine speed ratio = 0.029 km/h: 1 rpm.
SECOND SET OF CONDITIONS:
- Transmission range switch "OFF" (R, D, 2, L range).
- Throttle angle is between 20.0° and 44.0°.
- Engine coolant temperature above 60°C (140°F).
- Stoplamp switch is open (brake pedal released).
- Vehicle speed is between 35.8 and 5.09 km/h (22 and 32 mph).
- Vehicle speed to engine speed ratio = 0.029 km/h: 1 rpm.
ACTION TAKEN WHEN THE DTC SETS
- The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles with the malfunction present.
CONDITIONS FOR CLEARING THE MIL/DTC
- The Malfunction Indicator Lamp (MIL) will turn "OFF" after three consecutive drive cycles without a fault present.
- DTC will clear after 40 consecutive warm-up cycles without a fault.
- DTC can be cleared by using a scan tool or by disconnecting the Engine Control Module (ECM) battery feed.
DIAGNOSTIC AIDS
Check the following conditions:
- Torque Converter Clutch (TCC) relay for proper resistance values and operation.
- Torque Converter Clutch (TCC) solenoid valve and/or its circuit.
- Poor connection at the Engine Control Module (ECM) and at connectors C102, Cl04 and C301. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
- Damaged harness. Inspect the wiring harness for damage.
If DTC P0740 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions since the DTC was last set. This may assist in determining how often the DTC sets.
If any wiring repairs need to be made. Refer to "Repair Procedures" in Diagrams.
TEST DESCRIPTION
Numbers below refer to the step numbers on the Diagnostic Table.
1. The On-Board Diagnostic (OBD) System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. Checks the circuit that controls the Torque Converter Clutch (TCC) relay.
3. Checks the circuit that powers the TCC relay.
4. Checks TCC relay for proper resistance values.
5. Checks TCC relay for proper resistance values.
6. Checks TCC relay for proper resistance values.
7. Checks TCC solenoid for proper resistance values.
8. Checks Engine Control Module (ECM) operation of the TCC relay control circuit.
9. Checks TCC solenoid operation.
10. Checks power feed circuit between the Main Relay and the TCC relay.
12. Checks for a short to ground in the WHT wire between the TCC relay and TCC solenoid.
13. Checks for an open or high resistance in the WHT wire between the TCC relay and the TCC solenoid.
15. Checks the performance of the TCC.
16. Confirms DTC is set due to an ECM malfunction.
24. Confirms TCC solenoid is not leaking when off.
25. Confirms TCC solenoid opens when on.
26. Confirms a malfunction within the mechanical portion of the TCC and not its electrical components.
DTC CONFIRMATION PROCEDURE
The DTC Confirmation Procedure outline is here as follows:
1. Ignition switch to "LOCK."
2. Connect scan tool to Data Link Connector (DLC).
3. Start engine and warm up to normal operating temperature.
4. Clear DTCs, pending DTCs, and "Freeze Frame" data in the Engine Control Module (ECM) memory with scan tool.
5. Whenever possible, drive vehicle to 43 km/h (27 mph) in Drive "D" range for 10 seconds.
6. Whenever possible increase vehicle speed to 85 km/h (53 mph) in Drive "D" range for 10 seconds.
7. Stop vehicle and check for DTC(s) with scan tool.