check engine light-Engine Coolant Temp. circuit mal function

my 98 camry which has 62k miles on it has recently engine light pops up on it.
about a month back i observed this problem.when i stop the engine and started it ,it went off.after a few days it came back again and when i restarted engine it went off,but when i stopped at the stop sign.engine stalls,fortunately i was able to restart it and drove it.

i been to toyoto delaer and he replaced the water pump assembly.(he said this was required one machanic while replacing the thermostat broke the bolt and for that he need to replace the whole water pump assembly)

after a few weeks i saw the problem again.After i restart couple of times it check engine light cleared off.Now i dont have check engine light,but still i went to local machanic and test the malfunction codes,as it seems like it repeates after a interval(or after xxx drive cycles)

i saw it saying "Engine Coolant Temp. circuit malfunction" but i was not able to glance the code when my machanic readin the code.

now what he suggest me is there may be problem in "Engine coolant temp sensor" and which i should get it replaced.

i am not sure whether the problem is because of that or with some thing else.

how much it costs to replace that part???or do you guys think it would be problem with the "engine coolant temp sensor circuit" it self???
or is it because of water pump itself is not working???


By now i spent lot of money on it???i need your valuable suggestions.
please post your replies ASAP.

Thanks a Million in advance

If the water pump was not working,the engine would overheat in a VERY short time.
Autozone will read the codes for free,but a malfunctioning coolant temp sensor will make the engine run bad.

If the water pump was not working,the engine would overheat in a VERY short time.
Autozone will read the codes for free,but a malfunctioning coolant temp sensor will make the engine run bad.
Typical of a temp sensor. Very erratic symptoms. One of the symptoms is that if you let it idle until is warm up the cars stalls. If that happens then disconnect the temp sensor and try to start the car. Now the computer reading is telling you that the temp sensor or Engine coolant Temperature (ECT) is sending the wrong signal to the computer. I would change it. The part at a Toyota dealer should be not more than $40 and the instalation is very simple. It should take 5 min. If the ECT is malfunctioning will send a signal to the computer that would be interpreted as if the coolant is cold. The computer will send a signal to the injector to increase the gas. This will greate an enriched condition and your car will stall during idle at stop signs or when you ar getting off the HWAY.
Good luck

Typical of a temp sensor. Very erratic symptoms. One of the symptoms is that if you let it idle until is warm up the cars stalls. If that happens then disconnect the temp sensor and try to start the car. Now the computer reading is telling you that the temp sensor or Engine coolant Temperature (ECT) is sending the wrong signal to the computer. I would change it. The part at a Toyota dealer should be not more than $40 and the instalation is very simple. It should take 5 min. If the ECT is malfunctioning will send a signal to the computer that would be interpreted as if the coolant is cold. The computer will send a signal to the injector to increase the gas. This will greate an enriched condition and your car will stall during idle at stop signs or when you ar getting off the HWAY.
Good luck
Where is the temp sensor? Take a look in my gallery. The midle picture shows 3 sort of sensors. The third one on the left of the picture is the ECT. (It might slightly differ from the 98. This is a 95 4 cyl)

Where is the temp sensor? Take a look in my gallery. The midle picture shows 3 sort of sensors. The third one on the left of the picture is the ECT. (It might slightly differ from the 98. This is a 95 4 cyl)

the code was P0115-Engine coolant temparature Malfunction.

Mechanic replaced the Engine coolant tempareture sensor and cleared off the signal.i am driving since two days.for now there is no indication.
Hopefully that fixes the problem.

Thanks to your valuable suggestions and taking time to answer my question.Now i am confident that it fixes the problem.