Powertrain Controls - ECM/PCM

DTC 68 Trans Component Slipping:

TCC:

CIRCUIT DESCRIPTION
The PCM/TCM monitors the difference in engine speed and input speed. With transmission in "drive" and Torque Converter Clutch (TCC) locked, the scan tool should display engine speed closely matching input speed.

DTC 68 WILL SET WHEN
^ No DTC(s) 28, 71, 74.
^ TCC slip speed greater than 2O0 RPM.
^ Fourth gear is indicated.
^ TCC is locked.
^ Not in park/neutral.
^ All conditions are met for 2 seconds.

ACTION TAKEN (TCM will default to)
^ Inhibit TCC operation.
^ Inhibit manual mode operation.

DTC 68 WILL CLEAR WHEN
The fault condition(s) no longer exists and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks the indicated range signal to the actual selected range. A faulty switch could set DTC 68.
2. This test checks the torque converter for slippage while in a commanded lock-up state.

DIAGNOSTIC AIDS
^ Check for deformed connectors at pass-thru connector.
^ DTC 68 will set when going to default (second gear).
^ Refer to "PCM Intermittent DTC(s) or Performance. PCM/TCM Intermittent Diagnostic Trouble Code or Performance
^ An intermittent incorrect engine speed signal will set a DTC 68 if the incorrect signal lasts for greater than 2 seconds.
^ A mechanical failure in the 1-2 shift solenoid (stuck "OFF") or 2-3 shift solenoid (stuck "ON"), could set DTC 68.