On Board Diagnostics

RECENTLY THE LIGHT ON THE DASHBOARD DIED I WENT TO THE DEALER HE TOLD ME IT WOULD COST 90 DOLLARS TO CHECKIT AFTER A WHILE HE TOLD ME THEY CALLED TOYOTA AND THEY RECOMENDED
TO CHANGE THE COMPUTER AT A COST OF 700.00 I DECLINED PAID MY 90 DOLLARS AND LEFT ON IT OWN THE LIGHT IS BACK WORKING FINE

 

That $800 in total repair costs would cover, what, about two months of payments if you borrowed to buy a new one? The car sounds fine to me. I would get a new dealer instead.

 

You don't need a specific scanner to do basic "check engine" light diagnostics. Any off the shelf OBD II scan tool will give you the codes that are causing your light to illuminate.

The specific scan tool will give you extended information, such as engine RPM, battery SOC, etc. But for about 99% of your DIY maintenance, you won't need any of this information. It's really more for people who love to abuse statistics in Internet forums.

 

Thank you everyone for the comments. The CEL came back on yesterday. Went to AutoZone within 10 seconds, she found the code to be P1121 just like Toyota did. The CEL is off for now. Richard, I agree that I may need a new dealer!

 

P1121 is a common code to come up on the Prius. It seems it happens a lot. Our '09 did the same thing a year ago and the code was the same as yours. It has to do with the coolant flow control valve and the position of the valve. The valve is of course controlled by computers (ECU) and the computers checks to see if the valve moves properly when instructions are given to the valve by the various computers.

A Toyota dealer did the repair for me. They used the following parts.

16670-21010 Valve Assy, Water $72.01
00272-SLLC2 Super Long Life Coolant $21.51

Labor $193.19
Parts $93.52
Tax $7.72

Total $294.43

Your total might vary due to the labor rate or tax rate.

Patrick Wong or other experts might be able to give you more information as far as R&R on the valve. If you do the work yourself, make certain that you reconnect the hoses to the correct outlets on the valve (three of them) as they are not marked and are the same color (black). Also you have replenish the coolant as well as bleed the coolant system. From my understanding it is tricky to bleed the system, but can be done with patience. It is important to get all of the air out of the system, otherwise you may have problems with overheating which will cause damage to critical expensive parts.

That is what I know about the P1121 code, again it is a common code found on the Prius which will cause the CEL to illuminate.

Here is a write-up Luscious garage did on it.

Luscious Garage | Blog | Prius P1121: Coolant Flow Control Valve Position Sensor Stuck

Ron

 

Have you cleaned the air throat, that could cause a CEL, that and the Air flow sensor should be cleaned from time to time.

 

jpmyers is reporting P1121 which is a "coolant flow control vave position" trouble code. I don't believe it is related to the MAF on the Prius. Common MAF codes should read P0100 through P0104.

Please refer to Luscious Garage | Blog | Prius P1121: Coolant Flow Control Valve Position Sensor Stuck for more information concerning the P1121 code.

Here is a list of OBDII codes that is online. OBD Codes - Site Map

Ron