1G ECT sensor question

[SuperFudge]

Hey guys I recently noticed that my temperature gauge on my car started fluctuating from the half way point up to 3/4 then quickly back down to half. From what I understand the car isn't overheating, so I ended up doing the Key Dance to pull codes.

I ended up with code 22 and according to AllData that's a code for an Engine Coolant Temperature sensor, either voltage to high or low.

The question is what would cause the sensor to have a high voltage or low? Or should I just replace the sensor and call it the day?

I know that the ECT sensor is a thermistor and changes resistance with temperature. Once the resistance changes it sends a signal to the PCM which then sends signals off to other key valuable sensors in the car.

 

[JamesH]

Could be a few things. The sensor could be going bad an internally shorting or going open.

But also the thermostat could be sticking. So first I would verify your coolant temp is actually holding steady by way of a heat gun or finding some way to physically measure the coolant temp when it goes high.

I'm leaning more toward a bad sensor/connector issue at the sensor.

 

[Kait]

Could be a few things. The sensor could be going bad an internally shorting or going open.

But also the thermostat could be sticking. So first I would verify your coolant temp is actually holding steady by way of a heat gun or finding some way to physically measure the coolant temp when it goes high.

I'm leaning more toward a bad sensor/connector issue at the sensor.

x2, I agree.

 

[dmnall]

Hey guys I recently noticed that my temperature gauge on my car started fluctuating from the half way point up to 3/4 then quickly back down to half. From what I understand the car isn’t overheating, so I ended up doing the Key Dance to pull codes.

I ended up with code 22 and according to AllData that’s a code for an Engine Coolant Temperature sensor, either voltage to high or low.

The question is what would cause the sensor to have a high voltage or low? Or should I just replace the sensor and call it the day?

I know that the ECT sensor is a thermistor and changes resistance with temperature. Once the resistance changes it sends a signal to the PCM which then sends signals off to other key valuable sensors in the car.

Well is your CEL on? The reason I am asking, my 98 is doing something similar where it will go 3/4 then back to half, while my car was doing a precondition yesterday, I used the mechanic's Temp Gun and water was 206 @ the radiator cap and 186 at the cylinder head I did overfill the bottle but no boiling and no CEL on at all. Also I am betting my car has the same problem considering, Thermostat is opening, top hose is Hot as usual and lower hose lukewarm and fans are working properly.

Cheers,
Charlie