P1121-Coolant Flow Valve

If you have a check engine light and code P1121, your coolant flow valve needs to be replaced. Luckily, it’s not necessarily an urgent issue (unless you need to pass state inspection asap)!

The 2004-2009 Prius utilizes a 3-way valve to direct coolant flow between the engine, the hot coolant storage tank and the heater core.  It’s involved in heating the passenger cabin when necessary as well as reducing cold start emissions. 

The vehicles engine control monitor (ECM) monitors the position of the valve and checks for malfunctions by monitoring the various temperature sensors. If the valve changes position and no changes or slow changes in temperature occur, it will set the P1121 code. The only way to resolve this problem is to replace the coolant flow valve and flush the system. You may have additional codes (P1151, P1150) if the coolant storage tank is malfunctioning.

Luckily, you can restrict or stop coolant flow to either of these components and it won’t have any effect on the coolant flowing through the engine block and cylinder head. The coolant flow valve is mounted along the driver’s side frame of the engine compartment, near the radiator, and can be removed by elevating the inverter and pulling the valve out from the top. 

Contact us:

By Phone  844-447-7487

By Text 979-848-6868

By email: sales@hometownhybrids.com

Prius Battery Icon Q&A

We get a lot of questions from Prius owners about the battery icon located on the display. Watching the colorful bars fill and drain within the battery gauge can cause reassurance or anxiety for some, so it’s important to know what’s happening and why.  While it cannot provide you with precise data, understanding how this dynamic icon works can help give you some insight on the health of your hybrid battery over time. 

*These questions pertain to the 2004-2009 Prius, but can generally apply to other Toyota hybrids with the exception of the icon colors.

Q: Why doesn’t my battery icon stay fully green while I’m driving?

A: In general the car will try to maintain six blue bars on the display. This corresponds to a state of charge (SOC) of around 60%. This “extra space” allows room for energy recovered during regenerative braking or hill decent that otherwise would have nowhere to go and would be wasted as heat. It is rare to see a full eight bars on a healthy battery unless descending a hill or mountain. Even when the battery icon appears to show a fully charged battery, its actually representing a SOC of about 80%. If your battery was allowed to fully charge on a regular basis it would eventually succumb to premature aging.

Q: I’ve noticed lately that my battery icon is rapidly fluctuating from eight green bars down to two red bars and back. Is this normal?

A: No! A rapid fluctuation indicates that hybrid battery failure may be in your near future. Under normal circumstances, you should notice the battery gauge slowly filling up to six blue bars while you drive and back down to a few bars while stopped or idling. If your battery icon is behaving erratically, you may also have noticed that your engine sounds louder and the car seems to be hesitating more often. There may even be warning lights and a loud fan sound from the rear seat area. For more information on what to do when this happens, check out our FAQ.

Q: My battery icon drops down to a couple red/purple bars sometimes. Is this normal?

 A: If the battery is dropping down to the last few bars, it is typically due to sitting at a long stop light or idling with the car on while the weather is hot. This graph will help explain in further deital:

If you’re at a stop and the air conditioner is running, a two to three minute period is typical for the battery to discharge from six bars to two bars.  From the graph you can see six bars corresponds to 55-65% SOC and two bars is 43-47% SOC.  If we take the middle value for each (60% and 45%) that’s only a drop of 15% when your car goes from six bars to two bars.  

A perfect brand new Prius battery has a capacity of 6500 milli-amp hours. Let’s assume that your older Prius may have a battery capacity of about 5500mAh. A 15% drop for a 5500mAh means it dropped only about 800mAh.  The air conditioner and all the car components on a hot day will easily use 15 amps of current from the hybrid battery; 15 amps will consume that 850mAh in only four minutes. 

Q: When I park my car at night it has around six blue bars, but in the morning, it only has a couple red bars. Is my battery failing?

A: Possibly. The battery seems like it may not be holding a charge and should be monitored closely. There can be other conditions (regenerative braking failure or poor engine power) which cause the battery to not charge properly, but its most likely that it will need to be replaced soon. You’ll likely get a slew of warning lights on the dash soon and its imperative that diagnostic codes be checked before the battery is replaced. I wouldn’t advise taking any long road trips in the meantime!

Contact us:

By Phone  844-447-7487

By Text 979-848-6868

By email: sales@hometownhybrids.com

P0A93-Prius Inverter Water Pump

The Prius is always, sometimes an elusive creature and tracking down the source of seemingly random warning lights, sounds and smells is what we do best. 

Hi everyone, we are replacing several Generation II (2004-2009) Prius inverter water pumps lately so I thought it may be helpful to explain what to expect if yours fails and how it affects your wallet as well. The most common scenario we hear from our customers is that the infamous Triangle of Death appears, but the Prius still drives normally for short distances. When diagnostic codes are checked, the code present is P0A93. If the warning is ignored and the car is continuously driven, there is a great risk of overheating the hybrid inverter. An inverter replacement is much more costly and time consuming than simply replacing the pump, so my advice is to take action quickly. 

Typically, when the pump dies, its because its DC brushless motor fails internally. This usually keeps the warning light illuminated, but sometimes the failure may be intermittent and the warning light will come and go. If your having intermittent warning lights and P0A93 code in the diagnostic history, its best to go ahead and get the pump replaced. 

This little water of pump of doom can actually make the Prius stall…while driving. This is uncommon, but I feel it should be mentioned. When the pump shorts internally the AM2 fuse can blow, which in an unfortunate chain reaction, will cut power to the Power Source Control ECU (diagnostic code B1210). In this scenario you may have a burnt/electrical smell and you will definitely have a Prius that won’t drive until the pump and fuse are replaced. 

We’ve heard many of tales of misdiagnosed inverter water pump failure. One dealership recommended total engine replacement to remedy a shorted pump and fuse, but luckily the owner called us to get a second opinion. If you’re ever second guessing a diagnosis on your hybrid, please call, email or live chat with us! We can figure out most problems just by listening to your experience and the vehicles symptoms. 

Hope this helps! 

Our price: OEM inverter pump replacement is $395 in our mobile service area

Dealership price: generally between $600-$800 

Contact us:

By Phone  844-447-7487

By Text 979-848-6868

By email: sales@hometownhybrids.com