2009 Prius code P1121

Hello, this is my first post. Apologies if there is already a thread about this, but I haven't seen it at time of posting this. I have had a check engine light on my prius for over a year, our mechanic says that it is electrical and don't worry about it. We now have to smog the prius in CA this year and it won't pass with the Check Engine light on. Our mechanic tried to fix it and couldn't. I took it to Toyota in Hollywood and they replaced the Coolant Control Valve under warranty, but they are still getting the code and the Check Engine light is still on. After further diagnosing the prius, they suggested that I replace the ECU for $1170.00 thought they can't guarantee this is going to fix the issue. If it doesn't fix the issue they suggest that they replace the wiring harness for almost $7500. Has anyone experienced this problem and found a solution? I need to get it smog checked before the end of August, so time is not on our side. Thanks for your time.

 

Thank for your reply. Our mechanic just replaced the 12v Battery a week ago, so I think he tried that.

 

Hi Bisco, The Prius has 108,438. We are not the original owners, we purchased the car in 2012. The Toyota dealer checked to see if there is evidence of Rodent Problems, and they never found any.

 

I will check with my mechanic, but he has had it for a several days. Toyota performed an expensive diagnostic, I would like to think they would have checked something like that, but you never know...

 

That's what I thought. Toyota told me that the ECU is out of warranty which was 8 years/80,000 miles. Considering I got the car with 81,000 miles a few years ago I never got a detailed warranty for this car. Should I try to escalate this with corporate?

 

I checked the coolant and the radiator this morning before I started the car. The coolant in the radiator started to overflow as I was opening the cap, so quickly I closed it as it leaked onto my hand. Not sure quite why that is the case as the car was cold.

 

Thanks, that's a little beyond my abilities though.

 

Just a quick update on the Prius. I was able to get an extension on my Car registration till Mid -November. I still have the check engine light on. I don't know how to get this problem fixed. The dealer said to replace my ECU but that seemed expensive especially as he couldn't guarantee that it would fix the problem. My question is has anyone had to replace their ECU? Is it possible to do this without going through the dealer if I were to purchase one of the internet? Can anyone recommend a Prius specialist in Los Angeles. We really like the car and plan on keeping it, so we don't want to sell it and even not sure that we can in this condition. Any thoughts are welcome.

 

No I haven't tried to escalate this to corporate, I'm not sure how I could begin to do that really, any ideas?

 

I will try and contact them this week. My mechanic was telling me that the issue of buying a used one is that Toyota has to program it themselves, whether that's true or not I don't know.

 

Sorry it's been a while, but here is an update on this issue. I eventually had to take it back to the dealer and they replaced an ECU, and it fixed the check engine light so I was able to get it smogged and registered. Thanks to all the help that everyone offered.