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Automatic Transmission – 4L60E – Electrical Diagnosis Page 7C2–94 attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the ignition When the TCM detects a continuous short to voltage in the 1-2 shift solenoid valve control circuit, then DTC P0974 sets. Refer to 2 Wiring Diagrams and Connector Chart to aid in diagnosis. Conditions for Running the DTC • The system voltage is 8 – 18 V. • The engine speed is 500 r.p.m. for 5 seconds. Conditions for Setting the DTC DTC P0974 sets if the TCM commands the solenoid on and the voltage feedback remains high, battery voltage. Action Taken When the DTC Sets • The TCM requests the ECM to illuminate the MIL during the second consecutive trip in which the Conditions for • The TCM commands maximum line pressure. • The TCM freezes transmission adaptive functions. • The TCM inhibits TCC engagement. • At the time of the first failure, the TCM records the operating conditions when the conditions for setting the DTC are • At the time of the second failure, the ECM records the operating conditions when the conditions for setting the DTC • The TCM stores DTC P0974 in TCM history during the second consecutive trip in which the conditions for setting Conditions for Clearing the DTC • The ECM turns off the MIL after the fourth consecutive drive trip in which the TCM does not send a MIL illumination • Tech 2 can clear the DTC. • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission • The TCM cancels the DTC default actions when the ignition is off long enough to power down the TCM. Test Description The following numbers refer to the step numbers in the diagnostic table: 2 Checks the ability of the TCM to command the 1-2 SS valve. 3 Checks for a short to voltage in the 1-2 SS signal circuit. 4 Checks the serviceability of the 1-2 SS and the control valve body wiring harness. DTC P0974 Diagnostic Table Step Action Yes No 1 Has the Diagnostic System Check been performed? Go to Step 2 Refer to 4.7 Diagnostic System Check |