I had to pick up my mother's Civic from the mechanic and I asked him if he had an experience with Cadillacs. He said yeah and asked if I needed work, I said maybe in the future.

My car turned fine, everything smooth and I'm driving along when I notice out of the corner of my eye I got the "Service Engine Soon" light. I can't pull over, on the highway, and the person falling me, driving the Civic, is already late.

As I'm driving I also notice the temperature fluxating a bit. When I drive it mostly stays dead center, this time it went about 1/16 more towards the red. Is that normal?

I got to work and I turned off the car. I pulled the codes and got:
P0453 - Fuel Tank Pressure Sensor Circuit High Voltage

Any idea what could have set this code off? The car was fine between my house and the mechanic. I started laughing thinking the mechanic might have set off a signal causing the car to switch a code.

Could this be connected to my heat flux or am I just being paranoid?

where does your temp guage normally sit when driving and idling? for me it never goes above the 1/2 mark, it's always there. the one time i saw it go higher was when i was driving up the mountains (above 5,000ft) in colorado last year.

I wouldn't worry too much right now. if it continues or happens more frequently then i'd start checking things out.


I would clear all the codes and see if they come back, it's probably just a fluke!

just my 2 cents. :)

My temp guage will go a small amount past half way sitting in traffic when it's real hot. So as long as it isn't cranked over to the right, I wouldn't worry.

I've owned the car for almost two months now and of all the times it has always been right at the center, the temp guage.

This is the second time it fluxated, the last time I noticed it when I was parking the car.

When i first noticed it moving I revved the engine to about 3K RPMs and it didn't budge. I kept driving and I came to a red light thats when it started to rise up. It doesn't move a lot, not enough to cause serious alarm. But I will go ahead and change the coolant but I know it doesn't currently have Dexcool. How should I go about changing it now, and I don't know what current brand it is either.

As for my code, I did a search and found nothing. Only CTS and their tanks with the jet pump but I don't have any of those. On some other sites I found a few things to test out, so hopefully it is something simple like a new gas tank cap rather then a sensor.

Do not worry about slight temp. variations. It is normal. As for your code, most likely, you have a bad sensor. It is located on top of the fuel pump sender assembly. There might be an acess panal in the trunk. To test, there are three wire to the sensor.
Gray = 5 volt referance(from PCM)
Black = sensor ground(through PCM)
Dark Green = pressure sensor signal(to PCM)
Possible failures:
Either the gray, or dark green wire is shorted to battery voltage. This is very rare.
Black wire is open between sensor and PCM. Much more common.
Sensor is open.
Gray wire should have about 5 volts. The 5 volt signal should be ok, so measure from the gray wire to the dark green. Should also be about 5 volts. If not, you have an open in the dark green between the sensor and the PCM. If all this is ok, you have a bad sensor. Good luck, hope this helps.