So, a friend of ours father passed away and when he passed he was trying to trouble shoot his Crossfire for various issues. They knew I used to have a Crossfire years ago and said that it had check engine light on and other issues and they would just give it to me if I wanted to take the project on, so I did!

Problem is this pesky P0455 (large EVAP leak) check engine light code is driving me nuts! I started with the easiest/cheapest options first and still no luck. I’ve done the following so far

- Replaced fuel cap with new
- Inspected lines and hoses (that I could see) and did not see anything obvious or a fitting that was loose or broken
- Replaced purge valve solenoid (maybe it was defective?)
- Cleaned MAF sensor
- Replaced Fuel Vapor shut off valve gasket
- Bought used vapor canister to try replacing the “Fuel vapor shut off valve” which I couldn’t find by itself anywhere

Any ideas that I haven’t thought of?

It stinks because apparently I found out in Houston area that I can’t even transfer the title to me until it passes emissions (which it failed of course). After I get this fixed, I have a long laundry list of other issues like spoiler that is stuck up, AC blend door/control know issues (blows hot/cold fast/slow), hood strut bad, idler pulley bearings seem shot, no SRS lights light up which is a bit concerning, probably some other items too!

Thanks for any help

 

Sometimes "free" is the most expensive. Torque Pro ($5 and a $13 dongle if you have an Android device) should be able to monitor many things in real time, read and clear codes, and email results.

 

Get in the service manual, go to Chapter 25 "Emissions Control", then go to "Evaporative Emissions" in that chapter.
IGNORE the parts on the EGR and crankcase ventilation. Concentrate on the EVAP diagram, this is the system that is failing the test, if, indeed, it is really failing (keep reading).

KEEP IN MIND that the system may be just fine, and what you have is a flaky sensor or corroded connector on the sensor, this got me back in about 2010 with my first Roadster. The connector is in the top of the tank and I'd allowed water to get in the connector causing corrosion and setting off a P0453. With what you have, the sensor is indicating a large leak, which means the pressure indication falls too quickly once the system pressurizes. But again, the ECU may interpret unstable readings as a gross leak -unstable due to a poor connection or a failing sensor; you may or may not have a big leak. My BOSCH 1100 reader cannot see the sensor's output and besides, you must meet the criteria for the ECU to perform the test. HOWEVER: You could use a voltmeter to watch the reading and see if it jumps around a lot, it SHOULD be very stable both when the test is not running and when it is running. (Either around .9 volts or nearly 4.5 volts if I remember correctly.) If it is moving around a lot, the connection to the sensor is bad, the sensor is bad, or the supply voltage from the ECU is unstable (probably due to a corroded connector between the ECU and the sensor).

 

Thank you Pizzaguy for your reply and detailed suggestions. Yes, I’ve gone through the Evap section of the manual a few times but will go through it again. When you mention the sensor, which sensor are you referring to (or are you saying basically all the sensors in the EVAP system?). I don’t have a lot of experience unfortunately with a multimeter but may be able to figure it out and see what you suggested. Will give it a go. Thanks again!

 

Thanks, yeah you are right as free being the most expensive! Thanks, yeah I have torque pro and a cheap android phone I am using. I’ve reset the system many times but then I have to drive it for a while to reset all the monitors and of course the emissions test won’t pass if you have uncleared monitors. We’ll see what happens

 

The pressure in the tank during the EVAP test is measured by a sensor in the middle top of the tank. It's easy to see it in a Roadster.
There are two sensors, one for fuel level (has two wires) and one for tank pressure during the test (has three wires). You are looking at the level on the wire in cavity 1.

 

I forgot some things:

1) Cars that sit a lot or sit a long time can develop corrosion on wiring pins and terminals, these, again, can cause erratic readings which can fool the ECU.
2) Cars that sit can suffer from chewed wiring if rodents have access to the car.
3) If the wire in pin 1 has unstable voltage on it, check the other two pins to be sure the 5 volt lead is SOLIDLY at 5 volts, if not, you must trace back to the ECU to see what is causing it to be unstable.
If the ground pin has more than maybe .05 volts on it, you must follow that wire to the ground connection to see where the resistance is.

You could have a system leak, but you could EASILY have a wiring/sensor issue that makes the ECU THINK you have a leak. Don't go too far in "fixing my leak" until you KNOW that the 'leak' is real.

 

Thank you pizza guy for the detailed suggestion regarding checking the sensor and wiring. That is some good advice and I probably should have started there before replacing parts like you suggested. So, I was able to access the fuel tank pressure sensor and hooked up my multimeter. Couldn’t really get much of a reading which I thought was odd (but I may not have been using the multimeter correctly) or I have a wiring issue somewhere. I waited for a while until I think the test started as well and didn’t get much results. Will try again. I did also measure the wiring for the purge valve solenoid and it jumped up (when I think the test was running or trying to run). I decided to also hook up my old purge solenoid to some alligator clips and touched them to the battery, the old one was making the open and close sound. I decided to then test the “new” one I replaced months back. It was bad! It wasn’t making any noise of opening or closing. Ridiculous amazon junk I guess. Should have tested it before I installed it. After I replaced that sensor and nothing changed, I replaced the charcoal canister shutoff valve so now we’ll see if that was the issue and go from there. If not, then back to wiring diagnosis and trying to see if I have a bad fuel tank pressure sensor or wiring issues somewhere. Fun stuff! Thanks for the help

 

Use mainly Bosch electrical parts from Amazon or eBay. I only buy parts from RA I know will not be returned.