DS5 System Readiness Check Incomplete

Ah, the dreaded readiness monitors! Basically, your car runs a series of self-tests on its emissions systems. When you clear codes with an OBD2 scanner, you reset these monitors. They need to run and pass again to show the system is ready for an emissions test. It's super annoying. The car needs to complete a specific 'drive cycle' to get them to run. Has it been driven much since the OBD2 readout? What system shows not ready?

I've driven it a fair bit since. How can I determine what exact system is not ready, and what does completing a drive cycle entail?

You'd need to use an OBD2 scanner that displays readiness monitor status. It will tell you exactly which systems (like catalyst, oxygen sensor, EGR etc.) are incomplete. A drive cycle is a specific sequence of driving conditions – speed, acceleration, deceleration – designed to force those monitors to run. Honestly, finding the exact drive cycle for your DS5 and successfully completing it can be tricky. Some car manufacturers don't make this information easily available, and even if you do find it, replicating it perfectly is hard. If you recently ran diagnostics and now see that the system readiness check is incomplete, I would advise you to go to your local car repair shop. They know how to handle these things.

Thanks for the explanation. Turns out, the issue resolved itself after a longer drive. All monitors are now showing as ready. Cost me nothing!