I changed out the thermostat on my toyoto and now it does'nt overheat but the check engine light is on. Why?
The Check engine light is on if a fault code is logged in the ecu. It could be a fault in a sensor or it may be because it got a wrong reading from a sensor when the vehicle got hot. You need to clear the codes in the ECU. I don't know what model your car is so i am not sure how to do this. On alot of Toyotas you can disconnect the battery for a short amount of time and then re-connect it. That clears codes in some of the earlier models. Otherwise you need to find someone with a code reading machine and they can reset it for you
I changed out the thermostat on my toyoto and now it does'nt overheat but the check engine light is on. Why?
Michael does have a point. One the other hand.... What I have learned after 15 years in car business is that codes can be cleared, but if the check engine light comes back on take it somewhere to have the codes read so you know what's going on.
To properly reset the computer in your car these are the steps you need to follow.
1. Disconnect the negative battery cable.
2. Turn the key in the ignition 5 or 6 times. This drains any residual power that your car's computer may be holding.
3. Wait approximately 10 minutes.
4. Reconnect the negative battery cable.
If the check engine light comes back on do take your car to have codes read. Some auto parts stores will hook up a scanner to your car and pull the codes. Have them write down the codes for you for future reference just in case.
I'll give you an example of why I don't firmly believe it's bad to clear codes yourself the first time in a case like this. At once place I worked we sold 'nearly new' used cars. On average they had 10k on them after being pulled from the rental fleet. With the start of newer cars and newer systems we had some customers come back with a check engine light on. After some questioning a common theme appeared. They had recently fueled the vehicle. When I ran the scanner on the vehicle the code that came up was an %26quot;evap system%26quot; problem. What that translates to is the simple fact that they didn't put the fuel cap on correctly and the computer read that as a fault because the pressure wasn't correct in the gas tank, which can effect the engine. Also, most dealerships were charging between $60 and $80 for %26quot;fixing%26quot; the car. 20 minutes time at the most. How's that for highway robbery? At other times it was a minor fault code because of a battery or air filter change.
I recommend you get the codes read to determine what it is mad about. It could be trying to tell you something important, or at least something you should know if seemingly unrelated problems pop up later. Most auto chain stores - Autozone, Checker/Schuck's/Krager, NAPA - will read the codes and try to clear them (which turns off the light) for free in hopes they can sell you what you may need to fix whatever is wrong. Write the codes down unless you have a super memory. I had a super memory 30 years ago %26lt;8^)
I am not a fan of disconnecting the battery to clear a check engine light. Besides losing the potentially valuable information, some cars are not very graceful about it. Toyotas are pretty stable, but Fords usually have a period of poor response as the ECU learns how to run the engine again and Honda owners are always complaining about finding the anti-theft codes for the radios or trouble entering the codes.
try removing the negative battery cable from the battery then put it back on....this will reset the code reader and the light should go off....if it doesn't you'll have to do some more investigating
