failed smog test after replacing battery

I would think the changing of the 12 volt just resets your IM monitors and all that stuff should be I don't know 20 mi or something you should be able to be inspected something like that I don't think you have to drive anything out because changing your 12 volt doesn't set any permanent codes now if you have permanent codes stored you have to follow the procedures to drive those out which was just discussed yesterday here on this list but I don't think that's your problem but I don't know that.

 

That makes NO sense at all! NO reason for the hybrid to update,
driving doesn't update it.
It would have been smarter if they guy told you WHY it failed, so you could
resolve the issue.
So wait a few days and take it back, or to someone else. Go to your "mechanic".
So you can tell him you went. "IF" you fail, have they person tell you WHY it failed.
Then you'll have some place to start looking.
Are there and codes?

You need to get more info as to why it failed.

 

Disconnecting the 12v battery or resetting the stored flags will make your car fail the test until there has been enough new data collected by the ECUs to satisfy the emissions test. This can take several short trips or a couple of longer trips.

JeffD

 

You can get a Bluetooth obd2 interface for around $35 and then a phone app like “Car Scanner” which will list the monitors and their status.

This is a partial from my car:

 

Yeah those I am monitors mine are green almost immediately when I plug up another battery get in the car and start it up and they start turning green immediately and I wouldn't think any permanent codes would make any difference to the emissions test because the emissions test is looking at those I m monitors. And as soon as they're all green generally you're good for the test they don't care that you have a permanent hybrid battery code that makes no difference to emissions testing. Or a permanent break code or something I don't think it's going to matter.

 

Lab coat less answer. When a car loses power from the 12v battery, the car’s computer monitors that reports the status of vehicle goes off line. After a “drive cycle”, all monitors will comeback online and report the car status. A complete drive cycle will vary from brand and model of vehicle. Usually it’s half hour drive on the highway for drive cycle.

Some states dont require all the vehicles’ monitors to be online or functional to pass smog check

 

I believe there are default settings. When the power is disconnected, it defaults.
Then the car "learns" the driving behavior.

So the default setting will pass all emission tests. Unless there was an issue with a defective part.
But if all was fine before the battery failed, it will be fine after the car gets power back..

 

Gen3 Prius hold codes in memory after they've been clear for about 70 miles or so. So maybe what smog guy is saying is making sure the error codes are fully cleared?

If you have a one of these devices you can read and clear error codes yourself with Dr. Prius app or other apps: Panlong OBD2 Scanner Bluetooth OBDII Diagnostic Tool Car Code Reader Turn Off... | eBay

 

Post #6 showed the list of different monitor tests that the ECM performs.

In post 6, the "Result" for every one is showing PASSED.

The possible results are INCOMPLETE, PASSED, FAiLED, and UNKNOWN.

If you have had the battery unhooked, they all go back to INCOMPLETE. Assuming nothing is wrong, they will all eventually show PASSED again, but there's not a super simple answer about when. Each result depends on a specific test that the ECM has to perform under specific conditions. For example, the EGR test ($31:$BD) can only happen when you are decelerating for several seconds with a warm engine from above 25 MPH with the engine running (with fuel cut) instead of stopped. It will show INCOMPLETE until your driving happens to have hit the right conditions for the test to run. The catalyst test ($21:$A9) can only happen when the engine is warm, you're driving in closed loop between 10% and 70% engine load and the MAF reading and front / rear catalyst temperatures are in certain ranges. And so on.

The evap system tests don't even happen when you're driving, but several hours after you have parked and turned off the car (usually five hours, but depends on temperatures).

So there's no one-size-fits-all "do this much driving and they'll all be ready". If you do enough driving in enough different conditions, they'll generally all complete eventually without you having to think about it, and then you can go have an inspection done.

Naturally, if any test completes with a FAILED status, you'll fail the inspection. If any test is just showing INCOMPLETE, the inspection tech should just tell you to come back when it completes.

UNKNOWN is a weird case where the number of reasons a test can't be run yet happens to exceed the amount of memory the ECM was given to remember them, so then it can't tell when the conditions become right.

If you have an inspection date coming up soon and you've got one or two tests still showing INCOMPLETE and you're impatient, you can look up the "confirmation driving pattern" for each test that's still INCOMPLETE, and drive that. That's just a pattern that's pretty much sure to hit all the right conditions for that test to run.

One thing makes it hard to look up the confirmation patterns when you're looking at the list of tests: there's no nice list in the repair manual that shows the monitor tests and what their confirmation patterns are. Instead, you find each confirmation pattern by looking up the trouble code that you'd get if that test failed.

For example, if the test still showing incomplete is the catalyst test $21:$A9, knowing that the code you get when that test fails is P0420, you flip to P0420 in the repair manual and that's where you find the confirmation pattern.

One thing to look out for: in the manual, pretty much every confirmation driving pattern starts with "connect a scan tool and do a code clear". That, of course, has the effect of setting every monitor test back to INCOMPLETE, and you're back to square one. If you're in a hurry to get the board all green, you can't keep doing those code clears, but just try to hit all the remaining steps of the confirmation patterns you need.

 

The cat test takes the longest in my experience with older and newer cars alike. A highway run going 60-65 for a few minutes should do it. I don’t think more than 10 minutes. You could try that and see.

 

True dat.
Two weeks ago I replaced my HV battery at dealer. They disconnected 12V battery and when I took the car after replacement all those tests pictured above were Incomplete.
Two weeks later all are Passed again. Mostly city drive and short trips (30 miles) outside the city to my brother in law.