Circuit Description
The Torque Converter Clutch (TCC) Solenoid engages the lock-up clutch. The Powertrain Control Module (PCM) outputs system voltage in order to turn ON (energize) or remove voltage in order to turn OFF (to de-energize the TCC solenoid). The TCC solenoid controls the hydraulic pressure to the lock-up valve within the transmission. The TCC solenoid remains OFF in the 1st and 2nd gears. The TCC remains ON in the 3rd and 4th gears when the PCM deems appropriate. The TCC solenoid is never ON during 4L operation or when the engine coolant temperature is below 30°C (80°F).
Conditions for Setting the DTC
| • | The voltage detected at PCM connector C3 terminal 16 is 2.0V or lower when the PCM commands the TCC control solenoid ON. |
| • | The voltage detected at PCM connector C3 terminal 16 is 5.5V or higher when the PCM commands the TCC control solenoid OFF. |
| • | Two driving cycle detection logic |
Action Taken When the DTC Sets
| • | DTC P0743 stores. |
| • | The PCM enters the fail-safe mode. |
| • | The Malfunction Indicator Lamp (MIL) turns ON. |
The torque converter clutch does not engage during fail-safe mode operation.
Diagnostic Aids
Inspect for the following conditions:
| • | An open or shorted TCC solenoid |
| • | Faulty electrical circuits (open or short to ground) between the TCC solenoid and the PCM |
| • | A faulty PCM |
The following conditions may cause an intermittent:
| • | A reduced connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Inspect the PCM harness connectors for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Reduced terminal-to-wire connections |
If DTC P0743 cannot duplicate, the information included in the Freeze Frame data may be useful in determining the vehicle operating conditions when the DTC set.
Refer to Wiring Repairs in Wiring Systems when repairing any wiring.
DTC Confirmation Procedure
- Turn the ignition switch to the LOCK position.
- Connect the scan tool to the Data Link Connector (DLC).
- Turn the ignition switch ON.
- Use the scan tool in order to clear the following items:
- Start the engine.
- Warm the engine up to normal operating temperature.
- Shift the manual selector to DRIVE range.
- Accelerate the vehicle in DRIVE range.
- Stop the vehicle.
- Use the scan tool in order to test for a pending DTC.
| • | DTC P0743 |
| • | Any pending DTCs |
Remain in DRIVE range for 10 seconds.
Continue driving for 20 seconds at 80 km/h (50 mph).
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. The scan tool creates an electronic copy of the data taken when the fault occurred. The information then stores in the scan tool for later reference.
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This step tests the TCC solenoid internal coil resistance.
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This step tests for a short to ground in the GRN/YEL wire.
Refer to the above figure.
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This step tests for an open in the GRN/YEL wire.
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This step inspects the transmission internal electrical harness for damage.
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This step tests for a reduced electrical connection that may have set DTC P0743.
-
This step tests for a faulty PCM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | ||
Is the resistance within the specified range? | 11-16.6 ohms at 24°C (75°F) | |||
Is the resistance within the range specified in the Value(s) column? | Infinite | |||
Use J 39200 in order to measure the resistance between the PCM harness connector C3 terminal 16 and connector C104 terminal 8. Is the resistance less than the specified value? | 2 ohms | |||
Is the procedure complete? | -- | -- | ||
Is the voltage less than the specified value? | 2 V | |||
Inspect all of the electrical connections for reduced terminal contact or a reduced connection. Do reduced terminal contact or reduced connections exist? | -- | |||
8 |
Does DTC P0743 reset? | -- | ||
9 | Repair the short to ground in the GRN/YEL wire between the PCM and the TCC solenoid. Is the repair complete? | -- | -- | |
10 | Repair the open or the high resistance in the GRN/YEL wire between the PCM and the TCC solenoid. Is the repair complete? | -- | -- | |
11 | Repair the short to voltage in the GRN/YEL wire between the PCM and the TCC solenoid. Is the repair complete? | -- | -- | |
12 | Repair any terminals or connections that exhibit reduced contact. Is the repair complete? | -- | -- | |
13 | Refer to Diagnostic Aids for a possible intermittent condition. If OK, replace the Powertrain Control Module (PCM). Refer to Powertrain Control Module Replacement in Engine Controls. Is the procedure complete? | -- | -- | |
14 | Refer to Diagnostic Aids for additional information about DTC P0743. Is the action complete? | -- | -- | |
15 |
Does the scan tool display any DTC(s)? | -- | Go to the applicable DTC table | System OK |
