Toyota RAV4 Occasional high water temperature fault, water temperature light on

2012 Toyota RAV4 Engine 2.0 displacement 1AZ
AT automatic transmission

Fault phenomenon:
Occasional high water temperature fault, water temperature gauge reaches the top, water temperature light on
Water temperature is not high when entering the factory

Fault analysis:
High water temperature fault Simple analysis of 4 points
1 Insufficient coolant 2 Cooling fan does not work 3 Coolant does not circulate
4 Problems with water temperature sensor and circuit
Coolant is sufficient Test the working condition of cooling fan Directly turn on AC air conditioner
Found that the fan near the belt does not work, that is, cooling fan No. 2
Directly measure the cooling fan plug circuit Power supply is only 2.95V Normally, 12V power supply is required to control the fan to work
Abnormal Either the relay does not work, or the circuit is short-circuited or broken
Measure the power output of relay No. 2 to fan No. 2, broken circuit, no connection
Oxidation and broken circuit in the middle of the wiring harness