Any suggestions would be appreciated. The tachometer may stop functioning, then gages and dash lights start turning on erratically. Then the transmission starts shifting to 3000+ rpm (which is apparently a CVT safe mode). This electrical problem may start after a rain and is very sensitive to car washing; however, now it occurs almost anytime.
I’ve cleaned most of the CanBus connectors, rewired some bad splices in the BCU part of the harness and replaced the BCU but no improvement. The BCU and area around it are very clean and dry. I’ve not seen any corrosion anywhere in the car. I’ve also replaced all four wheel speed sensors.

Thanks,
Peter

 

Oh, here are my fault codes:

P1739 communication error, TCM/TCU solenoid
P1739/Not Present DME: Clutch solenoid – communication error.
P1749/Not Present DME: Secondary pressure actuator -communication error.
P1749 secondary pressure solenoid communication error. M52, Transmission control module internal memory
P1611, serial communication link fault with transmission control module, no message from TCM
P1613, communication fault with ABS/DSC module, No message from ABS/DSC module.
P1613, DME: Serial communication connection, ASC.
90-GM: Info-memory entry open circuit, power supply BC1
60-Kombi: Can-Bus off
61-Kombi: Can-Bus no communication.
67-Kombi: CAN Bus, no message 1 from KOM2.
51-Kombi: Fault in transmission management.
5E18/Not present ABS-DSC: CAN data fault from DME/DDE
5E16/not present ABS-DSC: CAN connection to instrument cluster.
5E11/not present ABS/DCS: CAN fault in control unit

 

Yesterday I cleaned several grounds plus the battery terminals and it seemed okay, even insensitive to a car wash but it was sick again this morning. I then tried removing the tachometer, which seemed to make it better. Time will tell.

Why would a tachometer be sensitive to wetness or maybe there are two problems, or maybe the tach is unrelated to the problem.

Peter

 

Usually there's fuse box is the hub to causing these issues. Check it for water damage