CEL Issue - Insight Needed

[Devon557]

Hello everyone,

I have a 2006 Ford Mustang GT and I am having trouble with a CEL, code P0453 (EVAP System Pressure Sensor/Switch Circuit High). I have already replaced the Fuel Rail Injection Pressure Sensor because I read that might be an issue, but no luck. Now I am considering replacing Evaporative Emissions System Pressure Sensor. Although, I am slightly at a loss. If it is reading high then it must mean it is working, I tested the voltage on it and it is getting the correct voltage on the one pin and nothing on the other two.

Any insight would be appreciated, thanks.

 

[Dino Dino Bambino]

A lot of people make the mistake of replacing any sensor that reads high or low believing that's the culprit, when actually it's merely doing its job detecting a system fault. The solution is to find and fix the underlying cause of the problem.
In your case, a high pressure in the evaporative system implies that there's a blockage preventing it from venting. There are three possibilities:

1. The canister purge valve has stuck closed (it's situated inside the driver's side strut tower), though that's the least likely since it more commonly gets stuck open and causes a big vacuum leak.

2. The charcoal canister itself or the piping to and from it is blocked. This assembly is situated under the gas tank and is easily accessible from underneath the car. I suggest you remove it, partially disassemble it, and blow compressed air through each component to check if it passes all the way through. You'll probably want to clean everything thoroughly before you reinstall since they'll be covered in road dirt.

3. Faulty fuel tank vent solenoid. If the previous procedure doesn't work, you might want to attach test wires (supply and ground) to the wiring harness connector pins directly from a 12v battery and see if it makes any sounds.

If you get no joy from any of the above, check for any shorts in the wiring to the fuel tank pressure sensor.

 

[JC SSP]

Always check your electrical connections and vacuum hose lines...

 

[86GT351]