Decat pipe?

Yes. You could just weld a pipe in place of catalytic converter. I don't think anybody sells decat pipe for a Prius.

Obviously you would get at lest P0420 catalyst system efficiency below threshold as the catalytic converter wouldn't work at all as it wouldn't even be there. That would also turn on your check engine light. Of course there would be ways around this problem.

Here they just put the Prius in maintenance mode and do the emission check normally. But even without that, wouldn't they see that you don't have catalytic converter, when they check the underside in the inspection?

 

CEL/DTC code (namely, P0420) would likely be cured with a $10 O2 sensor adapter with catalytic element. Adapter works to utilize catalyst only on exhaust being sensed by the O2 sensor. See: Oxygen O2 Sensor Spacer Adapter Bung Catalytic Converter Fix Check Engine Light | eBay

Auction is entitled: "Oxygen O2 Sensor Spacer Adapter Bung Catalytic Converter Fix Check Engine Light."

 

In NJ USA at state inspection, inspector usually just checks to see if CEL is illumicated and whether any DTC codes are stored.

 

Today, I spoke to a very learned mechanic here in NJ. He informed of the following:
1. 2000 and newer cars can pass NJ inspection with one pending DTC so long as CEL is NOT illuminated; and
2. 1996-1999 cars can pass NJ inspection with two pending DTCs so long as CEL is NOT illumonated.

 

IOW, a Prius with P0420 pending code should be able to pass NJ inspection without having to replace the catalyst (so long as CEL is NOT illuminated when inspected)..

 

In CT I could get my 2005 Prius passed emissions twice in the sweet spot between readiness codes getting set and Fault code (P0420) appearing.
I used ScanGauge II to reset and monitor codes including readiness codes. Some apps ( using bluetooth OBDII adapter) show individual monitors as well which ScanGauge II does not show.

Once the CEL got lit up less than half mile out of testing facility.

 

It's not the pending dtc's, it's the OBD2 readiness monitors. In NJ, a 1996 to 2000 car (or applicable light duty truck) can pass if it has up to 2 monitors "incomplete" or "not ready". A 2001 and newer can only have 1 monitor incomplete. The MIL must be functional and NOT on. (pending or history codes don't matter if the light is off)

There is (or at least should be) a visual inspection for the presence of a cat. The state run inspection facilities use a video camera mounted in the ground to view the exhaust as the inspector drives over. I believe a gross exhaust leak can also result in a failure.

Posted via the PriusChat mobile app.

 

Thanks for the clarification on pending DTC versus OBD2 readiness monitors.

Are readiness monitors the same as "mode 06" or "$06"?

 

My Prius fails the MID:$21 TID:$a9 test. See pic. It passes all other tests in $06. The pic is from the Torque Pro app's test results. Sounds like I have the "right" facts to pass NJ inspection (so long as CEL is not illuminated).

 

Each monitor can be a single test or might be composed of multiple tests. The results of those tests are displayed in mode $06. Most scanners have a separate menu to display the state of the readiness (or inspection) monitors.

Your car is good for inspection if it doesn't run and fail the cat monitor on your way over to the facility.

Posted via the PriusChat mobile app.

 

He was wrong, that's not dtc's. He's referring to IM readiness status. There is no such thing as pending dtc's. They either trip or they don't. You can have historic dtc's saved, if you don't reset your computer. I know because I lived in NJ.

 

There is a "Type A" emissions fault that will set a (hard or active) code the same drive cycle as it fails and turns on the MIL - this is known as a "1 trip code". The code is stored in OBD mode $03.

Then there is a "Type B" emissions fault that will store a pending code (in OBD mode $07) during the drive cycle that it failed. If the test passes during the following (consecutive) drive cycle, then the code self-clears. If the test fails during the following drive cycle, it "matures" to an active code, turns on the MIL, and is stored in mode $03. This is known as a "2 trip code".

OBD2 regulations are the same across the US, so where you live doesn't have much to do with how it actually works. I know, because I am an emissions repair tech in NJ.