Possible causes
– Faulty Coolant Flow Control Valve Position Sensor
– Coolant Flow Control Valve Position Sensor harness is open or shorted
– Coolant Flow Control Valve Position Sensor circuit poor electrical connection
– Coolant Flow Control Valve Position Sensor harness is open or shorted
– Coolant Flow Control Valve Position Sensor circuit poor electrical connection
Tech description
There is a Toyota factory service bulletin for the following Toyota models:
2004-2007 Toyota Prius
Toyota Factory Service Bulletin OBDII Code P1121
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
TOYOTA Related P1121 code
2004 TOYOTA PRIUS Engine And Engine Cooling
2005 TOYOTA PRIUS Engine And Engine Cooling