CEL light on (solid), red triangle with "!" on, and hybrid system malfunction light (car with "!")

New member with similar situation as titled on this thread, begging for help! A month ago, I bought a used 2004 with 116,000 at a good deal (I thought), but now this car is at my local dealership with a blown head gasket and a cracked block on the ICE and a probable cost to repair from $6K to $9K. When I first got the car, I drove it locally myself for over 3 weeks just to be sure that it did not have any issues. I have four salesreps on the road in Gen 2 Priuses ranging from 2004 to 2007 models that I purchased used and drove each of them a while to check them out, so I am relatively familiar with these cars. The weekend before I planned to turn this 2004 car over to one of my guys, I made a round trip of about 200 miles on it and the check engine light came on. I took it to the dealership and they said the Coolant Flow Control Valve was malfunctioning and would cost about $600 to repair it. I approved the repair and they had to order the part, so it stayed with them for 3 days. Got the bill and it was just shy of $600. I drove the car the next day with no problem so I turned it over to my sales rep and he drove it a few days with no problem. Yesterday he called me because he had problems. To start with, the dash showed a red triangle with an exclamation mark in it and the MFD had a temperature symbol appear in the upper section. He stopped and checked the coolant reservior and it was empty, so he added coolant. He restarted the car, and the red triangle! blinked four times then turned off but the Check Engine Light immediately came on again so he called me. I called the dealership and explained all of the above scenario to the service manager and he told me to bring the car back in. My salesrep was going to have to drive the car 80 miles to the dealership, so I asked the service manager if they had any kind of reciprocal relationship with the Toyota dealership in the town my salesrep was in, and he said no because all dealers are independent. So the next morning, my salesrep started the car and none of the warning lights were lit, but then a few miles down the road the check engine light came on again but he continued driving to the dealership with the check engine light on. About a mile before he got to the dealership, a yellow circle with parentheses around it and an exclamation mark inside it lit up on the dash, so he stopped again. When he got out of the car, he could smell something was hot, like electrical wires overheating, but he was so close to the dealer that he drove it on in. The service tech called me and said it was not good news because the water pump bracket had a crack which let the belt slip off the pump and let the engine overheat. I knew the recent repair involved the engine coolant so I looked at the invoice from that recent repair and the code was P1121 to replace the coolant flow control valve, and it also showed a $26.46 charge for super long life coolant #00272-SLLC2.

My questions are: 1)if they had to flush the cooling system of the ICE to replace the coolant flow control valve, shouldn't the technician have looked at the water pump to see if it had been damaged by the malfunction, 2)could the replacement of the valve have caused the engine to overheat such that the water pump could have started seizing up and caused the bracket to crack and the belt to come off, and 3) shouldn't the car have shut off or at least given the warning much sooner if it was about to overheat to cause so much damage to the ICE? I am very suspicious that the dealer's repairs created this calamity, but I need the knowledge of this forum to weigh in based on the facts as presented. Sorry this was so long but I wanted to provide as much detail as I could!

 

Concerning the throttle body failures this is why I bypassed the coolant loop in the tb on my 07. There's no reason to circulate 190F degree water through the TB if you live in warm climates. All it does is cook the tb motor.
Just remove the 2 hoses and re-connect them together using a brass barrel they use for PEX pipe found at Home D.
2 hose clamps and the tb now has 90F temps. Car runs great with a cooler intake.

 

Sorry to hear about your problem with this vehicle.

1. The coolant flow control valve controls the flow of engine coolant between the coolant heat recovery system canister and the cabin heater core. Its failure would not cause damage to the engine coolant pump.

2. Replacement of the valve would not cause the engine to overheat. By the way, the coolant pump is directly mounted on the front of the engine - there is no bracket. Is it possible that the service writer is referring to the idler pulley which is adjustable to set the serpentine drive belt tension and is mounted on a bracket?

3. The only warning that you will get when the engine is overheating is the red thermometer overtemp warning. That warning depends upon the temperature sensor in the cylinder head heating up. If fluid is not circulating past the sensor, you have to wait for the cylinder head to overheat for the sensor to register. If you continue to drive after seeing an overtemp warning, the engine will continue to run until it seizes up catastrophically.

An alternate repair approach might be for you to purchase a used engine from a salvage yard and have an independent install it. That might cost you <$2K. Good luck.

 

Wow I didn't know the throttle body is heated this way. In winter we see temperatures below zero F, occasionally -10 or -20 F. In this case does it still make sense to disconnect the coolant hoses?

 

No, unless you want to have the throttle plate freeze up in the open position during winter - and your car experience "unintended" acceleration.

 

Which is why my post said "if you live in warm climates".

 

Patrick,
Thanks for your reply and the info you have provided. I looked at the engine on our other 04 yesterday and could see both the water pump and coolant flow control valve, and as you stated, the water pump is mounted directly to the engine, so I was curious about where the crack in the bracket could have been. I am interested to look at the damaged engine to see if the bracket for the idler pulley is where the crack occurred. I think I will search for a used engine to see what I can find.

 

When I rebuilt my car, I could not get it to run correctly. I thought the problem was the TPS, but I adjusted it correctly. I brought the car to the local Toyota dealer, and they diagnosed the TPS. They told me a replacement part was $60.00 plus labor. They put it in, but it did not fix the car. It seems that Toyota used to sell the TPS by itself. I can't find it anywhere now. The TB can be purchased online new for about $650. I also found Holley univeral replacement TPS at the parts bin. Not sure if they will work, but if someone needs one, it might be worth investigation.

 

Probably has never had the throttle body cleaned before. It's really easy to do check back my old posts I have a foolproof method.

Our TB gets quite sooty like most modern cars. if the soot isn't routinely cleaned off the butterfly will get rusted and not open properly. TB motor will struggle with opening it and it will throw a Throttle Position Sensor nag.

The other about the Hybrid Battery doesn't sound good....or the 12 volt battery in the trunk is completely dead.

How many times have you had to jumpstart this car?

Ge the Hybrid battery sorted out. If the TB is toast you can buy a used one on eBay for $300 and any mechanic out there can install it. Its 3 bolts.

 

My daughter got the RED TRIANGLE OF DEATH!!! today on her 2008.

She limped it 1 mile home and I got the code reader on it. Just one code - P2103.

And thanks to this wonderful site, I was able to quickly determine that it is not the Hybrid Battery (that we've been dreading), but just a throttle body cleaning. Hallelujah!

30 minutes using some carb spray, an old toothbrush and a rag, I was able to get it ungummy. Also knocked the dust out of the air filter and shot the MAF with some MAF cleaner while I had the air cleaner off.

Cleared the code and test-drove it...Seems to run like a charm now.
I love this place. Thanks all.

 

well done! how many miles on her?

 

Are there pictures of this modification floating around?

 

Doubt it as I never posted any pictures and never heard anyone discuss it here before.
I see you live in San Francisco and have never been but I think you get pretty cold winters so may not be right for you. heated TB is to prevent vapor lock.
Mine has been bypassed for 10 years now on my car but Florida winters are very mild. Put on a jacket a couple of times all winter.

But it's easy pull the in and out coolant hoses off the throttle base and buy a 3/8 pex brass coupler and hose clamp it on.Tb goes from 190f to 85f.
Maybe just do it for the summer. TB motor will last much longer not being so heat soaked.

 

Was thinking of using a manual bypass valve (not exactly like the one below). But also working on how to make it automatic so it opens when cold (like below 50F) and closes when hotter.

Any ideas?

 

I like your engineering over the top as I suffer from that also but the single valve your showing is not going to work. You have to bypass the TB.
It would require 2 of these valves. But still a very nice idea. Trying to think where you would stow the 2 valves.
My car runs really good and has amazing pick up which I attribute to this mod. Would be interesting if you bypassed your tb and noticed a slight performance increase also which would not surprise me as cold air makes the engine run so much better. This is a very common cheap performance mod on cars.

 

Two 3 Way valves would do the trick.

Is this something to add to the June 24th to do list?

 

I finally got Torque up and running and tried the 'Knock Detector' plugin which offered an intake temperature reading- after driving around in the heat of the day I couldn't get it to go over 100F, which wasn't much above the outside ambient air temperature here.

Any idea how much lower it might be if one were to bypass the TB?

Also read on here (need to find it again) that the coolant thermos pumps a few liters during start up. Is this a one time event or does this happen whenever the engine cycles/restarts itself, and or is coolant constantly circulating through the throttle body while the engine is running?

 

The ambient air temperature sensor is in the air cleaner housing (part of the mass air flow sensor), hence it is upstream from the throttle body assembly.

The major reason to heat the throttle body is to prevent the possibility of icing developing in the throttle plate in cold weather, which would potentially cause an unintended acceleration incident. This is not a problem if you are driving in FL, however if you in San Francisco often take winter trips to Lake Tahoe then this would not be helpful.

Ed also pointed out that this modification results in not heating the throttle motor unnecessarily. This is true, however I haven't noticed that the throttle assembly is a high failure item.

Also, consider what is the potential benefit associated with reducing intake air temperature. The concept is that colder air is more dense. Denser air allows more fuel to be consumed given a fixed fuel/air ratio, providing more power.

If you will recall your high school chemistry course, you will remember that density of a gas is directly related to temperature in Kelvin degrees.

Suppose that this modification allowed you to reduce intake air temp by 20 degrees F, which is a change of 11 degrees C/K.

120 degrees F = 49 degrees C or 322 degrees K
100 degrees F = 38 degrees C or 311 degrees K

11 / 311 = 3% difference.

Recall that the ambient air temp sensor is upstream from the throttle body. So it is not going to signal a lower air temp to the engine ECU after this modification is performed. Hence the ECU is not going to pulse modulate the voltage going to the injectors at a higher rate to inject more fuel into the system.

Therefore, you are running potentially a 3% leaner air/fuel mixture via this modification during open-loop operation. That by itself is not going to produce more engine power.

If you could get the sensor to read lower, then you could inject 3% more fuel, and maybe realize 3% more power.

Once the air/fuel ratio sensor heats up and the ECU is operating in closed-loop mode then the air/fuel ratio will be optimized to take advantage of the slightly denser air.

Good luck perceiving any difference, other than wishful thinking.

The reality is that air flows very quickly past the throttle body, so a 20 degree F change is optimistic.

You can hear the coolant heat recovery system pump running (located in the left front fender ahead of the tire). It usually will run upon making the car READY, and again when you make the car IG-OFF. The purpose of that CHRS system is to encourage fast engine warmup, thus reducing exhaust emissions. This helped the 2G Prius qualify for CA AT-PZEV certification.

The pump does not run each time the engine cycles on/off during hybrid operation. Coolant is flowing through the throttle body assembly whenever the engine is running.

 

Throttle body temp by hand held IR temp gauge went from 190F to 98F. Probably colder than that when you are moving as there is quite a velocity of air moving through the tb. It may very well help with detonation. Costs $3 to try. 3/8 brass Pex barrel and 2 hose clamps. I highly recommend it as temps outside are nuts so much hotter. Even if I lived up north I would do it seasonally.

As far as definitive reported failures of the TB or any other failure we can only reference what we see here. But the vast majority of Prius owners are not on this site as Toyota has sold over 3 Million Prius in the USA since 2003.

Membership here is less than 2% of the cars out there.