CUSTOMER CONCERN Warning lights come on intermittently and DTC P261B sets because engine water-pump speed is below the commanded value. CAUSE A defective aftermarket electric engine water pump could not maintain the commanded pump speed. CORRECTION Remove and replace the defective aftermarket electric water pump with an OEM-quality pump, clear DTC P261B, and verify commanded and actual pump speed remain consistent.

CUSTOMER CONCERN The check-engine light returns with DTC P05A074 for active grille shutter actuator slipping after body repairs. CAUSE The active grille shutter assembly was missing the cover cap that retains the actuator, allowing the actuator and louver mechanism to slip. CORRECTION Remove and replace the damaged active grille shutter assembly, clear DTC P05A074, and verify the shutter completes its active test without slipping.

Diagnosing a 2017 Toyota Prius door lock that does not operate from the power lock system. Learn how actuator testing, Main Body ECU commands, wiring and the dash fuse/junction box can help isolate the fault before replacing components.