coolant heat storage (thermos), how do you test it?

In theory, DTC P1151 "Coolant Heat Storage Tank" is supposed to be logged if the tank outlet temperature during preheating is below 50 degrees C. An additional test is performed 5 hours after you turn the car to IG-OFF, and if the outlet temperature is more than 30 degrees C below the temperature logged during coolant recovery, that DTC will be logged.

So if you don't have P1151, the coolant tank is supposed to be OK.

What other DTC codes besides P1116 do you show?

 

DTC P1150 Coolant Path Clog Up implies a problem with the tank outlet temperature sensor, the water valve, clogging in the system, or the engine ECU (ECM).

The repair manual does not provide a spec for how long coolant should remain at a particular temperature. I don't have suggestions regarding how to check the tank beyond relying on the ECM to log P1151 if the tank has a problem.

Since P1116 and P1150 both point to the tank outlet temperature sensor, assuming you have no other related DTC, I suggest changing the sensor first. It seems you have sufficient evidence to diagnose the sensor as the failed part.

In your first post, you mentioned that you can read the temps of the engine coolant and the coolant tank as reported by the OBDII port. What readings do you get? Do those readings correspond closely after the car was driven and the coolant tank has been filled with hot coolant? If so, maybe the sensor is OK.

The manual indicates that the sensor resistance should be 2-3K ohms at 20 degrees C and 200-400 ohms at 80 degrees C. It also suggests using an infrared thermometer to read the tank outlet temperature in the vicinity of the sensor.

 

the temperature sensor or something might be bad. im not sure about the thermos though.

 

Are you sure the entire cooling system is fully purged of air, etc? It's gotten to where it can be tough to get all the air out of some cars. Did you just get it back from the body shop, or has it been like this for awhile?

I would be curious to drive it until hot, put it in Park, and have a helper turn the car off while feeling the hoses connecting the thermos. Is hot coolant going in to it in the first place? Do you hear the coolant transfer pump running at the times you expect?

To me the right way to check the heat storage ability of the tank is to confirm hot coolant going in, then fire up the Prius a few hours later and see if you can feel hot coolant going out of the thermos again.

P.S. The transfer pump in my 07 is dying a slow, grindy-sounding death, but it still working.

 

well, that's how you test it alright.

you still haven't ruled out the coolant control valve. if there is no hot coolant in the tank after 10 hours, it might not be getting there. properly stored coolant will still be hot enough to scald you after an overnight sit. if there is no hot coolant, of course the sensor reading is going to be low.

run the car until it's hot, park it, let chs pump run its cycle. crack the valve on the chs tank. if the coolant is hot, the chs tank is bad and is not keeping coolant hot overnight. if the coolant is cold, the valve is bad and no hot coolant is getting in there in the first place.

 

Re: Dented Tank along I-80

I just got a 2008 rebuilder in N.J. banged in the nose...How are these tanks made inside ? A glass liner on the inside? Are they pretty tough? If the tank has some small dents could it still be OK? ...Also..I need to find some one who has a frame machine along I-80 as my rails are over an inch ...I live in Idaho....fly back...then....gonna try to patch it up ...drive it home ...thanks all

 

Anyone have experience with DTC P2601, which is supposed to be the Coolant Heat Storage control circuit? I have gone through the repair manual and checked the wire harness, CHS water pump relay, CHS tank outlet temp sensor, and CHS pump. All measurements were within range at ambient temp. Is there a way to directly test the CHS water pump? Maybe directly apply 12V DC to the pump connector? I'm not sure what voltage the pump operates on. I get the P2601 code every time the car cools off completely, when turning it on for the first time each day. The dealer thinks power is not getting through the wire harness, but I verified each wire from the sensor to the ECM.

 

See my post #5 to the following string:
http://priuschat.com/forums/prius-t...lant-pump-operation-questions.html#post700377

 

Hello

Using and OBDII scanner, which PID or value corresponds to the temperature sensor of the coolant heat storage tank?

Thanks