Toyota Repair: Code 71 90 Cressida, vacuum hoses, heater control valve

Question
Hi Ted. My '90 Cressida got overheated last week due to a broken heater control valve. At the same time, the Check Engine light came on with a code 71. It's a California car, do you think the EGR temperature sensor got damaged from the overheat condition? The car ran fine for about 40 miles after I repaired the heater control valve and cleared the code, but now the code 71 has come back. Is there a way to check the sensor, or should I try cleaning the EGR passages first? Thank you!

Answer
I don't think the sensor was damaged to the overheating unless the wires melted, the sensor is usually exposed to exhaust gases which can reach 300 degrees, it's more likely that the egr modulator valve is bad, it's right on the EGR valve and has a few vacuum hoses on it, just try replacing it.