Sometimes your best diagnostic tool is your own hearing. Follow this Real Fix to see how a stethoscope was used to find the cause of a cooling problem on this Toyota Prius.
Vehicle
2001 Toyota Prius 1.5L
Title
P3130, Replaced Engine Water Pump
Complaint
The customer states the check engine light is on.
Cause
Connected a scan tool and found code P3130 – Inverter Cooling System Malfunction. Performed a road test while monitoring the inverter temperature parameter on the scan tool and found the high voltage inverter temperature parameter exceeded the specified range. After the vehicle to cooled down a visual inspection was performed of the hybrid engine cooling system and no obvious faults were found. The high voltage inverter coolant level was correct and the coolant was clean. Used an electronic stethoscope to hear the engine water pump operating, found that no noise was produced. Started the vehicle and used a multi-meter to check for voltage at the engine water pump. Found the voltage was present. While the engine was running, inspected the inverter coolant reservoir and found there was no circulation, which indicated the engine water pump was faulty.
Correction
Replaced the engine water pump, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.