Possible Causes
Coolant Flow Control Valve (Stuck or Clogged Cooling System)
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
Faulty Engine Control Module (ECM)
الأسباب المحتملة
Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
الأعراض المحتملة
Description
Code P1121 Toyota Description
The Engine Control Module (ECM) monitors the position of the water valve based on the valve position signal that is output by the water valve position sensor (potentiometer), which is coupled coaxially to the valve. The water valve effects control in three steps as indicated above, and the ECM determines the position of the valve according to the voltage of the respective step. In order to ensure the proper monitoring of the water valve, the ECM checks for malfunctions with the combination of the output of the potentiometer and Coolant Heat Storage (CHS) tank outlet temperature sensor. If no changes occur in the valve position signal that is being inputted into the ECM or if the response signal from the water valve is very slow, despite of the ECM commanding the water valve motor to operate the ECM determines that malfunction has occurred in the water valve position sensor circuit, and sets a Diagnostic Trouble Code (DTC).
P1121 Toyota Code – Coolant Flow Control Valve Position Sensor Circuit Stuck