Help With Codes

[dryeriii]

Hello Forum, You have helped so much in the past I'm hoping you can help now.
Took my code reader out to the van and pulled the following codes,
P0420 Catalyst Efficiency below theshold (bank1)
P0452 Evaporative emission control system presure sensor low input.

Ok, now where should I go from here? Oh might help if I told you it was a 1998 Venture from California 168000 miles on it.

[DRW1000]

Originally Posted by dryeriii

Hello Forum, You have helped so much in the past I'm hoping you can help now.
Took my code reader out to the van and pulled the following codes,
P0420 Catalyst Efficiency below theshold (bank1)
P0452 Evaporative emission control system presure sensor low input.

Ok, now where should I go from here? Oh might help if I told you it was a 1998 Venture from California 168000 miles on it.

My guess is that they are separate faults (ie not related to one another).

P0420 Catalyst Efficiency below theshold (bank1) - sounds like one of your catalytic converters is not operarting correctly

P0452 Evaporative emission control system presure sensor low input.- This is the system that captures fuel vapours and then routes them back to the fuel tank.

Remember though with any code you are only reading that the PCM is reading an out of range value. The failure could be upstream from the questionable sensor or can be in the circuit or the wiring itself. The codes are only going to point you to a starting point for your troubleshooting.

[theshackie1]

First code usually relates to oxygen sensor located after catylatic converter

second code usually loose or faulty gas cap

[bcdodge]

I have no experience with the first code but the second I do. P452 senses the vapour pressure in the fuel tank. While it might go away if you clear it more likely it may be a poor fitting fuel cap as suggested or in my case it was the little sensor on top of the fuel tank. Check with your dealer, chances are that the parts dept has one on the shelf and they will tell you they sell lots.
Ps I changed my in about a hour, just run the tank low first, two bolts and the clamp for the filler hose I think. Good luck