06 prius red triangle and no power steering. Codes p1121 p1116 p1150

not that i know of. sounds like it is time to check for other codes.

 

All three of the listed codes have to do with the engine coolant system. The engine coolant valve may be stuck or there may be air in the coolant system.

Do you see a power steering system warning on the MFD display?

As bisco said, it would be good if you could retrieve the DTC associated with the electronic power steering system. You may need Toyota Techstream (or Mini VCI) to achieve that.

 

Do you have sufficient air in your front tires?

 

A PS display on the MFD, indicates a problem with the electric power steering of the car. Get it scanned first. A tech stream might help you

 

I just got the P1116 and P1121 codes recently and plan to do the following:
2008 2nd Gen with 168K miles purchased in 2008 with 15K miles on it.
All parts new Toyota OEM.
ENGINE ITEMS
-drain system
-water pump
-thermostat + gasket
-serpentine belt
-refill with SLLC
INVERTER ITEMS
-drain system
-water pump
-refill with SLLC

Finally, Clear codes either with my scan reader or disconnecting negative ground from battery to frame.

Can you guys advise me to do anything else? The only thing I'm not certain about is the location of the thermostat. Big job, time consuming, lots of youtube videos and videos here too.

Thanks!
Stoner

 

There are two main reasons for DTC P1121 showing up: either the engine coolant valve has failed, or else the engine has air in the coolant loop which causes the engine ECU to think that the valve is not working correctly. Air in the coolant loop is one reason why P1116 might be logged, the other is that the sensor located at the coolant heat recovery system canister actually has failed or is disconnected.

Your list of planned maintenance items may be necessary, however they will not directly address P1116 or P1121 unless air is in the engine coolant loop.

Hence I suggest you add to your first list the replacement of the engine coolant valve.

Regarding the location of the engine thermostat, it is where one of the radiator hoses connects to the engine. See my post here:
How to replace engine coolant pump and thermostat | PriusChat

 

Patrick,
Thanks for your reply. I have already reviewed your procedure and getting prepared for the job.
I have been mistaking the Engine Coolant Valve with the Inverter valve and thought it was the inverter valve causing the P1121 code
**I think air did get into the system as I recently had to put about 16 oz of distilled water in the radiator and reservoir and have noticed the level has again gone down in the radiator and a bit in the reservoir.
**I have noticed pink crystals around my engine coolant pump and its original so time to change.
**I will check the electrical connection at the CHRS canister and change out the sensor if the other items plus bleeding the system doesn't work.
**I do plan to change the engine coolant valve (I listed it under Inverter items and called it "water pump" above). Since the engine coolant pump, engine coolant valve, thermostat and fluid are all original, I am basically adding changing the engine coolant valve to the list like you suggest.
I should be able to find the thermostat from your photo and description.
I will let you know how it goes and thank you very much for all your fine, fine posts, replies and assistance to the Prius Chat community.
Stoner

 

Actually, since you know the engine coolant pump is leaking fluid and that air has been trapped in the system, it would be OK if you defer replacing the engine coolant valve until you've changed the other parts, then see if the two DTC go away, or persist.

 

Patrick,
So I got a head start today and accomplished the following today instead of watching football:
1. Removed left headlight assembly and removed bottom debris deflection skirt
2. Loosened the inverter bolts and the engine coolant bolts
3. Sprayed liquid wrench on the engine coolant pump screws to let the oil penetrate overnight
4. Located the hose where the thermostat is located and hit the screws with liquid wrench

Think I will go ahead and do the engine coolant valve as its easily reachable/removable with the left headlight out. That way, everything should be done of note.
My 3 gallons of SSLC is arriving the 3rd and my inverter arrived today. Hope to receive water pump, thermostat and engine coolant valve tomorrow or by next weekend.
All good so far.
Stoner

 

Regarding the use of liquid wrench, take a look at the idler pulley which exerts tension on the serpentine belt. The bolt which is coaxial to that pulley is the one which can be difficult to remove. Use the correct 6-point socket when removing that bolt and a cheater bar to increase leverage, so that you do not end up damaging the bolt. That bolt needs to be loosened, then you can rotate the other bolt on the pulley bracket to drop the pulley downwards, thus releasing tension on the belt.

You are also replacing the inverter? The two DTC that you posted are not related to that part, BTW.

 

I'm replacing the Inverter cooling pump I believe its called. Located behind the left headlight.
I figure, why not...it's about time to change (its approaching 100K miles) the fluid might as well change the inverter pump from what I read here on Prius chat.
I will go back and review draining the cooling system on the Inverter side and the engine side. I want to ensure all the old fluid is drained. If I open the drain valves on the CHRS, radiator, and remove the drain plug bottom of engine will that get all the fluid out on both sides? Are there any other valves to open?
Stoner

 

Keep in mind that the inverter coolant pump was the subject of a recall. You may want to look up your car’s dealer service records to see whether that recall work was done or not.

Regarding the engine coolant, I believe you will find that draining from the CHRS canister valve will take out 99% of the coolant. Once the fluid is drained at that point, the radiator drain will do nothing and only a very tiny amount will come out of the engine block drain.

The inverter coolant drain plug is on the bottom of the transaxle, closest to the engine.

 

Patrick,
My inverter recall was done at 90K miles. I now have 168K and figure since I'm right there removing the coolant control valve, might as well do them both.
Thanks for the info on draining both coolant systems.
I will get started as soon as I get the parts I need. I can find them on Amazon, Ebay but for some reason the water pump is taking 2 weeks to ship! I'd like to get it by Friday...I've tried ToyotaParts.com and one or two others recommended here.
Stoner

 

You tried any local dealers and see what they have in stock or places like autozone or oreilly’s?

 

Yes, but staying with Toyota OEM. I know I will pay a bit more
Stoner

 

OEM after the car has left the production line is normally Aisin or Delco .

Might be worth exhausting all options if you are on a timed schedule. The pricing shouldn’t be too much different given this is a mechanically driven pump and not magnetically driven like the Gen3.

Good luck and happy new year.

 

Thanks and Happy New Year!
Stoner

 

I wouldn’t be comfortable letting your Prius sit for too long given the hv battery is 10 years old (soon to be 11) and has plenty of miles on it.

The battery likes to be used and having it sit for a couple of weeks awaiting a repair is not good for its health .

So a problem could get worse if not careful.

Happy new year and good luck .