P1121 2007 Toyota Prius -

Question

Hi! My 2007 Prius has ~110,000 miles. 2 weeks ago, engine light came on and it was diagnosed at a trusted repair shop as P1121. Sadly they do not work on hybrids. I took it to dealer and they made repair - I don't have receipt available right now, but I think to coolant valve (or sensor??) for about $450.

Last night, engine light back on...back to trusted repair shop this morning and it is showing again as P1121. Dealer has me coming in tomorrow to diagnose/repair, but said there are several coolant valves/sensors and so it could be same repair on a different valve/sensor or something more simple. Looking for some insight before I go to my appt tomorrow. THANKS!

Answer 1

if they charged you diagnotic fee (that suppose to mean they checked all the possible causes) and they say "this is the problem" that was "suppose" to fix the problem. they cant sell you every possible sensor that could cause the problem. 

There is 3 valves and they can check the voltages on them to see if there are working correctly, if the valves are showing the correct voltages there might be a coolant clog somewhere or worst case scenario the computer is bad

see diagnostic procedures from Toyota below.