2AEC - Nitrogen Oxide Sensor Self Diagnosis

2A98 - Crankshaft - inlet camshaft, correlation

2AAF - Fuel pump, plausibility

So just a brief description, Bought my car just over 6 months ago, has run beautifully!

sometimes, I say sometimes it seems to be a pattern that when I start my car early in the morning between say 5-9 am when its at its coldest and drive away (after about a 2-3 minute warm up ) the engine yellow warning will appear, if I then pull over turn the car off and turn it back on its then fine for the rest of my journey with no light, and there are no issues. the warning will stay on continuously unless I reset the ignition as stated. However if in the morning I warm the car up for a good 5 - 10 minutes before setting off on my journey then the light never comes on? 5 - 10 minutes seems a long time to have to warm the car up for and I'm wondering if this has any connection to the warning codes that I have?
What is the severity of these warning codes?
anyone had similar experience?