Got several check engine lights....

Hey guys, I’ve got several check engine lights and just want to run thoughts by you guys. I’ll be doing the work myself. It’s a 2009 Touring with 123k miles.

P0171 system too lean bank 1
P0420 catalyst system efficiency below threshold bank 1
P2195 oxygen af sensor signal stuck lean (bank 1 sensor 1)

P1116 coolant temp sensor circuit stuck for coolant heat storage system
P1150 coolant path clog up for coolant heat storage system.

I’m thinking the upstream a/f ratio sensor needs to be replaced. Not sure about the rest of the system or if it’s really the af ratio sensor or really a lean condition BUT the car is running fine, not rough or anything so doesn’t seem like a vac leak or anything like that. I’m not sure about the coolant issue, maybe the coolant control valve?

I’d love a little feedback!

Thanks guys!

 

I replaced the battery with a brand new one less than a year ago....but I’ll doubt check it.

I believe the 2195 came on first several months ago and I have been planning on replacing the upper a/f ratio sensor since the car drives fine, but went to recheck which code it was Friday and saw the two new codes 0171 and 0420 (not sure exactly how long they have been there)

Then the coolant stuff came up for the first time today when I checked the codes again....so they just came up in the past couple days.

 

I replaced the ICE water pump (and I think thermostats) a year ago with a new one from Toyota along with Toyota coolant and also new spark plugs at the same time. I can hear the little electric water pump running and see the coolant flow through the little reservoir.

Doesn’t burn any oil.

What 3 way valve are you referring too? I’m not sure what part that is.

 

I am, that is what prompted me to get online. I wasn’t too worried about the exhaust but when I saw coolant codes that took it too a new level. Lol

 

Do you happen to know what voltage range it should be in? I looked at it via scan tool and it does move up and down with me giving it gas....but I’m not sure if it’s in the right range or not. I looked for the correct range but couldn’t find it.

 

Is there a good way to check it? Will the tank be cool instead of warm/hot if it’s not working properly?

 

123k miles

What do you think about the other 2 exhaust codes? The 2195 code started a while back so I’ve been planning on replacing the upstream af ratio sensor for a while. But do you think the 0171 and 0420 are being thrown because the a/f sensor is out, or is that a separate issue? The 0171 is a general lean condition issue the ecu sees....but is it possible the ecu just sees that because the up stream af sensor is bad and stuck lean? Or is it more likely that the car is actually lean? It’s running fine so I don’t think there is a vac leak, the maf seems to be okay based on watching scan voltage. It has plugs less than a year old. Runs and idles good. I’m just not sure that the bas O2 would be triggering the other 2 codes. Could the 0420 cat out of threashhold be caused by a bad downstream o2? Surely with 123k on a car where they ICE doesn’t run all the time, the cat should still be okay.

 

If the 3 way valve you mentioned cause both of those codes? It seems that both codes happened at the same time.

 

Okay I found this on a old thread posted by dolj related to P1116....

P1116 2006 TOYOTA PRIUS - Coolant Temperature Sensor Circuit Stack for Coolant Heat Storage System

Possible causes
- Coolant Heat Storage Tank
- Faulty Engine Coolant Temperature (ECT) sensor for CHS (Coolant Heat Storage)
- Low engine coolant level
- Engine Coolant Temperature (ECT) sensor for HST harness is open or shorted
- Engine Coolant Temperature (ECT) sensor for HST electrical circuit poor connection
- Faulty engine coolant thermostat


SOOO now I’m wondering if any of these possible causes for 1116 would cross reference/relate with p1150 which I’m thinking is probably the 3 way valve

 

Just to document....I found this by galaxee on another thread related to 1150....

*****
hmm. chs water pump had nothing to do with the p1150 code.

could be the coolant flow control valve or a clog/air in the system, or that sensor.

not the same as the engine coolant temp sensor. all the chs temp sensor does is detect that there is coolant flowing past it and that the coolant is hot.

since they opened the coolant system, there may be air in there. but from the sound of it, the code was present prior to you taking it in, right?

next is to verify the tank is storing hot coolant. when you know there's no air in the system, run the engine till it's hot, let it store hot coolant, and park the car overnight. come back the next morning, access the drain port on the bottom of the chs tank and crack it open a little bit. (get your hands out of the way.) look for a little steam as you run a little coolant out of it. then you know it is storing hot coolant and so then it would be either the sensor or the flow control valve. probably the temp sensor.

you haven't diagnosed the problem to arrive at the conclusion the sensor is bad, unless you're cool with shotgunning it.
*****

 

I cleared the codes yesterday and the coolant heater storage system codes haven’t come back. I’ve driven about 50 miles to see if they come back. Would it happen to be normal that these parts/sensors just get flakey with age and throw a code from a brief hiccup?