P0770
DTC P0770
Circuit Description
The powertrain control module (PCM) uses signals from the vehicle speed sensor to detect torque converter clutch (TCC) lock-up status. The PCM then compares the actual data with the TCC lock-up schedule in the PCM memory to detect mechanical trouble of the TCC solenoid and valve body.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0770 Torque Converter Clutch (TCC) System Performance
Conditions for Setting the DTC
DTC P0770 will set when one of the following conditions are met:
^ TCC lock-up does not occur after the PCM commands the TCC to apply.
^ TCC remains locked-up even after the PCM commands the TCC to release.
Action Taken When the DTC Sets
A DTC P0770 is stored and the malfunction indicator lamp (MIL) is turned ON.
Diagnostic Aids
Inspect for the following conditions:
^ Clogged or leaky TCC solenoid
^ Valve body fluid passage clogged
^ Torque converter clutch malfunction
^ Faulty PCM
If this DTC cannot be duplicated, the information included in the freeze frame data can be useful in determining vehicle operating conditions when the DTC was first set.
DTC Confirmation Procedure
1. Turn the ignition switch to LOCK.
2. Connect the scan tool to data link connector (DLC).
3. Turn the ignition switch to ON.
4. Clear the DTC, the pending DTC, and the freeze frame data in PCM memory by using the scan tool.
5. Start the engine and warm up to normal operating temperature.
6. Use the scan tool to monitor the operation of the TCC solenoid.
7. Accelerate vehicle in Drive (D) range and drive at 80 km/h (50 mph) for 10 seconds.
8. Stop the vehicle.
9. Test for a pending DTC with the scan tool.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check - Vehicle, 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.
4. This step checks for proper shift points.
5. This step checks for a stuck closed lock-up solenoid.
6. This step checks for a leaky lock-up solenoid.
7. This step checks the condition of the valve body assembly.
8. This step checks for a faulty PCM.
