Check engine light "ON" after New inverter water pump installed

A check engine light is usually emissions related. The possible areas of failure would be

1. Catalytic converter
2. 3 way coolant valve
3. Bad gas cap
4. Dirty/bad MAF sensor
5. Bad spark plugs
6. Bad coils

These would be the top reasons for that light.

 

You can drive it until your smog check is due....then it would fail smog. At that time, you put it on "NON OP" status. Then you can sell it.

Without it being on "NON OP", you would not be able to sell it. As CA transfer requires a passed smog check.

Alternatively, you can donate it to hobbyist like myself LOL

A new catalytic converter in CA would cost $2500, and on top of that, if your HV battery is original, that may be another $3500 failure waiting to happen.

 

No not normally. You have to acknowledge the codes to be cleared and generally parts houses will not clear codes due to liability reasons at least in my area. They simply read the codes and then the customer needs to determine the repair(s). Again I'll caution anyone using readers that are not fully compatable with these cars you may not get the right code and other codes may not be read at all. It's best to buck up and go to Toyota and pay the man for the codes or purchase a compatible reader for these cars such as the Mini VCI.

In your situation whichever ECU triggered the DTC, those conditions have not been met again to trip the light. If you pull the codes again you should see the same DTC code unless you disconnected the 12 volt battery and in essence wiped the DTC out of memory. When the conditions are met again the light will be triggered again.

 

Toyota and Subaru set p0420 VERY easily, very well before any efficiency loss of the cat can be detected during emissions tests.

There are any number of causes for the P0420 DTC, only one of which is actually a failed or failing "cat".

Common things that can cause P0420 are:
- oil burning (wear, bad pcv valve, overfull of oil, etc)
- exhaust leak
- lazy O2 sensor (rear)
- worn out WBO2 sensor (AFR sensor, front)
- poor air/fuel metering
- tune up
- defective sensors (other than O2/WB O2)

P0420 + Red Triangle Disappeared after 30 min | PriusChat

 

How's your oil consumption?

 

Hence, 1 quart per 1,000 miles or so?

That is a very high oil consumption rate and it is not surprising the catalytic converter is wearing out since it has to deal with excessive HC in the exhaust gases. The root cause is a severely worn engine which is not surprising after 243K miles have been logged.

If you haven't replaced the PCV valve recently, you could try that - but don't expect a big change in the oil consumption rate.

 

My thoughts (guestimate actually) exactly!

Eh, it's certainly high, but within Toyota's published guidelines, if barely. I am continually amazed at how many oil consumption complains lead directly to PCV valves. It takes just a little carbon on the "jiggler" to cause a depression in crankcase pressure and the resulting oil loss. You are spot on tho, if the engine is worn, it won't make any real difference.

 

Compared to our 185k Prius that *might* burn a whole quart in 5k.