HYUNDAI SONATA P0765

 

This Hyundai was sent to me to diagnose a random failure of the overdrive solenoid

circuit. The scope connections are: The blue trace is the overdrive solenoid circuit

at the PCM, (yellow/white) the green trace is the overdrive solenoid circuit at the transaxle.

The tan trace is the second gear solenoid connection at the transaxle, which shares

the same power input as the overdrive solenoid to the transaxle.

The red trace is a low amps probe at the PCM.

 

The circuit is clearly failing inside the transaxle, but one question should be answered yet.

Is it going open, or is it grounding? What changes in the connections could be made to

prove that fault before any disassembly is done?