2019 Tahoe and the check engine light came on. Diagnostic code P06DD which gives me “engine oil pressure control solenoid valve stuck off” I have an appt with the dealer in 2 weeks. They are really backed up. In the meantime though the check engine light has gone off. Can this issue resolve itself? Is it safe to drive the vehicle until my scheduled appt?
Bottom line, if the light went out, it's probably okay. The CEL has to do with how the oil pump works. There are two modes: high and low pressure. Here's the write up on it from obd2-code.com:
... the engine oil pump features seven vanes and a moving element that continuously adjust to maintain a regulated oil pressure supply by varying the displacement of the pump. The pump has two regulated pressure stages of operation controlled by an on/off solenoid. Low pressure mode regulation (solenoid on) is approximately 200 kpa (29 psi) and high pressure mode regulation (solenoid off) is approximately 450 kpa (65 psi). The Powertrain Control Module (PCM) switches the pump between stages based on engine operating conditions, oil and coolant temperatures, speed and load. Under most typical conditions, the pump will run in low mode from idle up to around 3000 rpm and switch from low to high mode between 3000 and 4000 rpm. The maximum oil pressure in the engine is limited to 1000 kpa (145 psi) by the relief valve. Pressure in the main oil galley of the engine can be monitored with diagnostic equipment through the oil pressure sensor. The minimum pressure for the engine is 41 kpa (6 psi) at any operating condition. Anything under this pressure could result in damage to critical moving part.
Considering the code is for the solenoid being stuck in the "off" position, it means you'd be getting higher oil pressure than it normally would at lower engine speeds. This really isn't an issue. I believe the main thing the engineers were trying to do here was to allow the engine less oil pressure at low speed so there'd be less drag on the engine, which will allow for lower fuel consumption.
If this was stuck in the "on" mode, you'd only get the lower pressure. In that case, I'd suggest it could be an issue because when the engine needed the higher pressures, it wouldn't be getting it. I don't think it would kill an engine, it just wouldn't be good for the engine. In your case, I don't think it would cause any issues other than possibly a little less fuel economy.