Hello, I'm glad to answer your questions. Unless this problem is eliminated after the engine failure light will be turned off, if the water temperature sensor voltage is higher than the normal value of the fault, the components involved are lines, sensors and ECU, of which the probability of problems in the line is greater, the troubleshooting steps are as follows:
1. After the vehicle is powered off, unplug the sensor and ECU wiring harness, use a multimeter to measure the connection between the sensor and ECU, if there is a connection, please check the breakpoint;
2, use a multimeter to measure the resistance value of the water temperature sensor, confirm whether the resistance value is normal, such as infinity, replace the water temperature sensor;
3, you can try to 5v power supply line behind the ECU plug, cut off, and then restore the harness plug, the whole vehicle power, use a multimeter to measure whether the line has 5v\/12v voltage, if there can be proof that the line and other firewire short-circuit caused, find the short circuit point, or replace the engine harness;
4. Replace the ECU. If the temperature sensor and voltage are not high after the ECU is replaced, replace the ECU.