Need Advice-Considering 2011 Prius, "Monitor Not Ready" CAT/EVAP/O2

Was the engine hot enough to get good readings? Could it be that trouble codes were cleared recently and the car needs to be driven a few more miles before it is ready to report those numbers?

 

After a code clear, the emission-test monitors will show "not ready" for a certain number of driving miles, before current results will be shown again. It works that way to thwart attempts to pass emission inspections by clearing trouble codes just before going in for inspection.

If they showed COMPLETE at some recent time, and now they show NOT READY, there has been a code-clear done since that earlier time. If buying the car, it's in your interest to inquire why, and what the codes were that were cleared.

 

Mileage is high and these cars are prone to head gasket issues at high mileage. I wonder if the seller did this work to try and solve a misfire code prior to selling the car. If you reset a check engine light, it can sometimes take 50-100 miles for all monitors to run and pass.

 

Given how valuable it it would be to have proof of that good stewardship, you'd think he'd at least try to get a duplicate of the receipt from the shop that did it. Hmm.

Yep, about right. Bail out, research another one.

 

Monitors scans the car while driving for any critical problems with certain systems such as EVAP, which then trips the CEL when something wrong detected. When you unplug the 12v battery from the vehicle system or use a OBD2 reader to turn off/erase the CEL code(s), CEL goes away, and all monitors goes to an offline state. When plug 12v bat onto system & start car, each monitor has their own interval when to run/scan test the car. Some mechanics have told me monitors may take up to 50 miles of HWY driving to come back on-line and begin scanning again but in my opinion it changes from manufacture to manufacture.

In CA, smog check doesn't require all monitors to be on-line to pass smog check. One time I had 4 offline and still passed but it wasn't the critical monitors they said.

Since it's the EVAP monitor, don't walk away from it. RUN.

 

From my point of view, this one had three screaming red flags (the guy taking off was #3) plus the unspecified yellow flags you mentioned. And you were still thinking about it. Think about that. I think you need to work on dismissing unfit candidates earlier in your checkout process.

 

The Prius is a popular car with many on the road. A good candidate for purchase should not be too difficult to find.

 

Only mine is still popular with me, so you can't have it.

 

Sounds fishy to me too.... There are more fish in the sea. If it walks like a duck, quacks like a duck and looks like a duck, it's a rat

 

Anything that walked, quacked, and looked like a duck in 2019 may well sound like a fish and smell like a rat in 2023.

 

Lol