2005 Dodge Grand Caravan SXT, 3.8l engine 41TE transmission.
I read P0740 from ECM and B0138 from TCM, it says that Torque converter clutch control circuit is open.
I "reset" the TCM by disconnecting the battery and drain the circuits. Codes come back.
If I reset the codes the transmission shifts fine and I can see on the tachometer that the TCC engages. After driving some miles, between 10 and 15 approximately the check engine light comes back and the same codes are there.
I have checked the contact from the Solenoid unit, both on the unit and the TCM and they look fine, I sprayed them with WD40. Didn't help. Then I took a chance and replaced the Solenoid unit. The lamp and codes still come back. It seems that this happens after a bit of time and I wonder if it may be an issue with heat in the TCM.
I have a Foxwell N680 PRO scanner, which data should I read out to find where the issue lies?
Any hints on more things to try out?