Common vac source problems occur at the motor source block.

I can't say what the codes are at home , but I agree to ignore them including the one about the aux water valve. Your problem is too much heat. The pumps do short and as a short might take down the controllers abilities (protection) to control the heater valve. If this is the case just disconnecting it should stop that problem (it will still set a code).

The problem with hot and cold should be in the heater valve or its control.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician