2010 Prius Check Hybrid System

Hey all. I've been experiencing some intermittent issues with our 2010 Prius and wanted to see if anybody had any ideas of where to go with it.

It seems that about every 100 miles or so the Check Hybrid System warning comes on. At this time it actually seems as if its mostly using EV and the ICE goes into a limp mode. I'm getting 3 codes using a basic obd2 adapter (2 of which point to a bad o2 sensor, and the other is low engine power). If I clear the codes, I'm able to drive the car with no issues.

I've already ordered the replacement o2 sensor but I am also wondering if my basic bluetooth obd2 adapter with the torque app is enough to read prius specific codes? Any input is always appreciated.

 

145k miles. I also performed a battery recon using hybrid automotive system about a month ago, and the battery is behaving a lot better in terms of not dropping down as quick as it used to. I never had any warnings about the battery I just wanted to start preventative maintenance.

I find it interesting that when the check hybrid system warning comes on that the engine is barely running and it uses mostly ev, and that once I clear obd2 it's fine. Just got the o2 sensor today so we will see.

Codes are p2196 p2238 and p3190.

 

@bisco yes I did (see attached it was pretty dirty), however that was right before I posted this thread and the check hybrid system message came back after the cleaning. I replaced the o2 sensor today and I'm in the middle of drive cycles hoping all checks clear.

 

Well 400+ miles after replacing the Air/Fuel Ratio Sensor (Bank 1 Sensor 1), all seems to have cleared up! Still waiting on the o2 readiness to finalize but no Check Engine Light or Codes returned so far. For anyone needing to replace this, please be sure to get the correct Air Fuel Ratio Sensor and not an o2 sensor for Bank 1 Sensor 1. The Gen 3 Prius is a Front AF Sensor and Rear O2S System. I'm still happy I cleaned that HV Battery Cooling Fan though. Thanks for the input and I will report if anything returns.

 

Ahh the dreaded CEL is back again. This time its throwing P2238 O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 1. So it's something with the same sensor but the car is running great, and it takes 700-800 miles before throwing the code. Any ideas on what I could check next? I've done the following:

* Replace the sensor.
* Replace engine air filter and cleaned mass air flow sensor.
* Tested all fuses inside and out.

Could it be that I didn't use OEM denso? Is there a relay I need to check? As always any input is appreciated.

 

It just came up on 5k to change oil, so I'll check the level in the morning. I never thought to check that.

 

I just checked it this morning and I'd say it's down about a half quart of oil after 5k miles. Not sure what that indicates or how that would affect o2 emissions? I am planning on cleaning the intake manifold, egr pipe and install an occ in the next week or so as preventative maintenance, but I also didn't think the o2 sensor issue would relate to that either.

 

Understood and I appreciate the input. I'm probably going to bite the bullet and order the denso one and hope it makes a difference. The only reason I'm thinking it may be this is that it takes so long before throwing a code, as if to say it's almost working but just falling out of range slightly.

 

Dude thank you so much for this! I will get measuring the next chance I get

 

Do you happen to know if there is a relay used with the air fuel ratio sensor?

 

Well I'm extremely happy to announce that the issue has been solved! Lesson I've learned is you have to use OEM parts. After putting in the Denso 234-9090 Air Fuel Sensor, the DTC monitors cleared after less than 30 miles over a few trips. Thanks again @Mendel Leisk for your help in troubleshooting.