That is typically the case when the cooling fans are on full blast, typically if it is real bad you can see or smell a burn mark or spot in the PCM itself.You would have to check the power and grounds to the pcm itself to be sure nothing is causing a voltage drop or short to power or ground where you should have battery power and ground. P0606 Indicates an interal PCM failure as described by the trouble code desciption.Indicates register readback error(PCM Internal Communications fault).Suggestions the PCM is damaged or defective and also states that for ETC applications that a PCM failure or a Failure Management mode condition exists.
P1233 says the PCM isnt getting a fuel level siganl from the REM module which can also be attributed to the PCM internal communciations fault, if the pcm can think,it wont recognize outside multiplexed inputs.
You would need to make sure the electronic throttle body itself isnt shorted out internally.You can disconnect the throttle body tps and actuator connector and see if the other codes go away,indicating a fault with the throttle body actuator itself which do go bad, but it sounds like the control portion for the ETC in the PCM is at fault. A test of the wiring between the ETC and the PCM to check for short to ground,power or open circuits would need to be done to rule out a wiring issue. Possibly a coil spiking or high altenator output can cause the pcm to fail. Below are the PCM connectors to check for B+ power and ground and identifies the circuits for the ETC system. Sounds like a bad PCM pretty much.