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Home >> Jeep >> 2024 >> Grand Cherokee Altitude X, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 45 (8HP75 Automatic Transmission - DTCS P1500-00 To P1D98-00) >> DTC Troubleshooting >> P1D78-00-Park Solenoid Circuit Low >> Theory Of Operation

Theory Of Operation

WARNING: This page is about a different car, the 2024 Jeep Grand Cherokee L. However, it is still accessible from the selected car via links, so may be relevant.

The Transmission Control Module (TCM) measures the actual solenoid voltages and compares them to calibrated values to identify the following electrical failures:

When the solenoid is switched on (i.e. commanded control value is 100%), the diagnostic can not distinguish between short to ground and open circuit. In that case, the Application-Specific Integrated Circuit (ASIC) status information is used to detect the failure.