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Thank you in advance. I appreciate any help. Now that I'm stuck at home I thought I'd look into this.
Code P0450 evaporative emissions control system pressure sensor malfunction.
This code has been on for 3 years. I've cleared it a few times but it comes back.
I haven't cleared it for over a year. These are the current readings from techstream.
I noticed the O2 sensor status was also reading incomplete. Here is the live data. Is this O2 sensor a separate issue, or maybe a non issue? I assume the red numbers are from the o2 sensor. Maybe someone can educate me.
The car runs great, no issues, 220k hard miles.
I do change the tranny fluid and engine oil very often. This was its last tow before I replaced all 4 springs and struts.
The most probable cause for that code is a faulty pressure sensor, since the condition at which it pops-up is if the sensor value didn't change after 10 seconds. To check the valve, go under the car and check if you have voltage coming to the sensor. If you do, use a syringe to make a vacuum inside of the sensor, and while doing that, measure the voltage across the second contact of the sensor, it should drop as you apply vacuum. If that is all good, you can try measuring the voltage across ECU pins shown below, you should see the same value as during the vacuum test.
While under the car, it is a good idea to check all the wires and hoses, see if there any cracks or stuff like that. Just in case..
Also, it does seem like you took a screenshot of the Techstream right after you started the car, since the idle is high and O2 sensor doesn't have any voltage. If it doesn't throw any CEL, you can try following a drive pattern to set it (see the attached PDF file).
Thank you for the flow chart link. It does appear the O2 sensor requires the cel to be off to complete the readiness check. It looks like the pressure sensor was the hang up for the O2 issue. And you were spot on about me just having started the car. Good eye!
Is it this pressure sensor we are talking about? I notice there is some sort of sensor or valve with 3 lines below it too. I took the top sensor out of the car. It must be part of the readiness monitors, after 3 starts the cel never came on ( the sensor was not hooked up)
I don't remember the exact voltage the pressure sensor plug had but it was around 4.5 volts. It has 3 wires. 2 of them were hot with 4.5v
.
Yes, it does seem like a correct sensor. The valve with three hoses coming to it is a Vapor Pressure Sensor VSV, which, as I understood is used by the ECU for the EVAP system self-diagnostics.
Back to the sensor - you need to measure the voltage across the middle contact and the ground while applying vacuum to the hose. As the pressure goes down, you should see the voltage drop, and vice versa.
97es300 code P0450 , screenshots
