I am seeking enlightenment and recommendations on what to look at and/or try, to prevent a single fault code, PO245, from being generated and the associated CEL (Check Engine Light) from illuminating.

The scenario: Using a OBDII Code Reader, the fault code is erased and the car’s memory is then confirmed to be clear, which also resets the CEL. The car is then started and within seconds the CEL illuminates and the PO145 fault exists. No other faults are generated. The car operates normally and smoothly with no degradation in performance in all ranges of driving. After a full drive cycle there is still no change in the CEL or fault code. I then repeated the process: (erase the fault code, confirmed memory was clear and started the engine) with exactly the same results.

Fault Code PO245 - Turbocharger Wastegate Solenoid A Low

My question is: "What are the top three things that could generate just the PO245 fault immediately upon start up, and still allow the engine to perform as good as new?"

I performed searches on the Brickboard Forums for "PO245" and "245" without finding anything that would help. I am hoping that the collective knowledge base and brainpower of those that use this Forum might help me.

FYI: As part of a planned major self-service this last weekend, I pressure washed the engine compartment (being careful not to get moisture near the ECU box, alternator or fusebox area). Then replaced the following; Spark plugs, Cap, Rotor, Ignition Wires, Timing Belt, Serpentine Belt, Fuel, Air & Oil filters, gaskets on the turbo oil drain tube, Brake Rotors & Pads, Instrument bulbs (all 25), Rear Hatch Struts, Trani fluid and coolant, installed the IPD Upper engine mount, and cleaned the throttle body. I mention the pressure washing and parts replacement as maybe it or they attributed to this fault?

Thanks in advance for your help.
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Original owner of 1996 TLA Limited Edition 855 T with 71 K miles. She receives lots of regular care and feeding and n return, I continue to get a great ride. Looking forward to driving my way to 200 k on the odometer.