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Discussion Starter · #1 ·
Had the engine light pop up. Used my OBDII scanner and .....
P0452 EVAP Pressure Sensor/Switch Low

Made an appointment at the dealer and after about half hour the service writer came to me and took me out to my car (up on the lift). Explained to me that they can see signs of where a mouse has been in the engine bay. I knew that because the little bugger ate my rubber hose to the windshield washer which I fixed. Cleaned everything up, covered the hose with wirewrap and threw some mouse bait in a couple places. Have since caught the little bugger and hadn't seen any signs lately. the tech explained that he looked all over and traced the Pressure Sensor wire back to the fuel tank. They needed to drop the tank (2 hours labor at $97 an hour) and replace the sensor or find out what the problem is. If it's the sensor, it's covered by warranty but if there's any signs of mouse chewing on the wire on top of the tank, then it's all my responsibility. I asked about leaving it and they said won't hurt anything, so I did for now. Went home and took my scanner and tried to clear the code but it kept saying "Erase Failed", so I still have the DTC light on. I do a lot of my own work but Cruze still being under warranty, don't want to tackle it myself so when I have more time to spend at the dealer waiting around (no way to get home from there) I'll go back and hope it's a failed sensor that needs changing and no signs of some little bugger having lunch on my wire. They didn't charge me anything for the hour they spent on it.
 

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According to my manual, the light will clear itself after 4 ignition cycles where the test runs and doesn't fail. The memory will clear after 40 warm-up cycles without failure.

P0452 can be set by either a open or a short to ground - certainly a possibility for a wiring problem. The manual doesn't give me any suggestions for troubleshooting malfunctions. If it was me, I'd re-inspect the wiring.
 

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On my 2nd day as a brand new owner I too had my first fault without an engine light or a code to read. My steering wheel spoke to me and the rapid ding feature stayed on for almost 2 weeks. Steering wheel said there was an engine fault and to turn engine off immediately.
 

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Its a common winter cold up here or is this a code. Usually is set at a steady speed, ECU gets bored and decides to run an evaporative emissions test. A normally vent valve mounted at the rear of the tank closes, and the purge valve by the engine opens to the intake manifold.

This draws a vacuum from the tank that the pressure sensor, actually more of a lack of pressure, a vacuum should cause its reading to shoot up to a volt, if it doesn't after a given time period, that code is set.

So whats the problem, the sensor, or a vacuum leak someplace? Most common is a loose gas cap, around here in the winter with all that salt slush, this gets into the canister all in a very stupid location mounted by the gas tank. Would love to meet the people that decided to put it back there in a dark alley. Carbon gets soaked with water, gets into the vent valve, and won't let it close.

Have to tell you these young kids designing our vehicles are complete idiots, for years that canister was mounted high on the fire wall along with the vent valve. Can't even believe that guys that call them selves engineers would even do something like this but does save a hose and you have those a$$hole bean counters.

Yes I hope you are ready this for the grief you are causing the consumers. Have an emission test up here also ran by even more idiots and if that code is set, you don't pass. Have to get your vehicle in a warm spot to dry out, not easy if you live in an apartment building, a kid in college and don't have any extra money.

You can realized I am frustrated with this stupid problem, already getting robbed to death with tuition payments skyrocketing because they claim all the money is for a stupid war, crooks around the university charge outrageous rents for building that should have been condemned a long time ago, then you have these kind of vehicles on top of that. If that carbon canister is shot because they dump loads of salt on sand, that's another 170 bucks out of your pocket and this is DIY.

Also problems with the filler hose, can't run a decent pipe, using rubber hoses for links, rust builds up on the inside. If lucky, the vent valve is frozen, can thaw that out and hope it good again, and it doesn't freeze up again so your kid can pass that emissions test.

Can also have a leak in any of the three fuel lines between the tank, use to be only one, now three, one for the fuel, another for the fuel return, need that to keep fuel flowing in that in tank fuel pump, dang thing is made so cheap, will burn up without fuel flow to cool it, than a vent line for the evaporative system.

Cruze cut that down to two, because the moved the fuel regulator back into the tank, with even a very minor leak, would get a code because air is far less dense than gas, but still have that vent line that doesn't carry fuel.

Kind of a trade off, one less line to check, but if your fuel regulator goes bad, instead of around 30 bucks for a new one, part of the fuel pump assembly that cost 250 bucks to replace it with a ton of labor to drop the tank.

So what is your problem, vacuum sensor, or a minor leak someplace? Don't know until you check, some use a smoke test, feel this is kind of dump. I energize the vent valve to close it, adapt a gas cap to a monitored vacuum pump, while monitoring that sensor output. Also, if that vacuum does not hold, you have a leak, someplace, anywhere between the gas filler tube to the front of the engine.

Does this fuel evaporative system really work? I don't feel so, major source of fuel evaporation was the carburetor bowl itself. When they got rid of that, think that should have been enough, but the EPA sure didn't think so. But still doesn't solve the problem if you have a fuel injector leak.

And is running unshielded wires your problem or the vehicle manufacturers problem? Not only unprotected from varmints, but also road salt. And you wonder why we have problems.

Ha, you got me started again. But fuel evaporative was far less of a problem when the components were mounted high above on the firewall, but sure is a problem now.
 

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In this case, the book indicates that the voltage is very low - either shorted to ground, open, or the sensor is missing the 5V reference signal. No indication that the pressure itself is off. It seems more of a failure of the sensor or wiring.
 

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Close call with the P0452 code, if greater than 0.15 V its okay if less than 0.15V for more than 0.1 s, code is set. Would think if a mouse got under there, an open circuit would be far more likely, lots of plastic under there for a short to ground.

Just find it quicker to apply negative pressure to see if it holds, then check the sensor output for voltage, see shops spending hours on this at 90 bucks an hour. Won't get into finding the right wire, easy on other vehicle, can take all day to find this in that stupid Cruze manual. Is possible the 5 volt line was cut.

New sensor runs about 50 bucks.







Now what about the integrity of your dealer, unless watching that you can't do due to liability issues, could say a mouse chewed the wire when the sensor is the problem. Wish I wasn't so paranoid. But again, not born this way, made this way.

What a difference an access plate would make!



#4 is the fuel pressure sensor.
 

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Discussion Starter · #7 ·
Nick. I had the same thoughts about dealer saying it's the mouse and it's really the sensor. Was thinking the exact thing last night and came up with a plan to hang around the open bay if it's not too cold when I take it in and watch when the tank is dropped. It's "chilly" here in central Florida in the mornings and warms up nicely in the afternoon. The bays are usually open (if it's not cold) and the rear of the car is only a few steps from where I can stand and watch from outside. The moto "trust but verify" comes into play, so I should be able to get a good look at the top of the tank when it's dropped to see if there's any damage by varmints (a troublesome wild animal). Thanks all for responding.
 

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Should take a poll to see how many people would pay a couple of bucks extra for an access plate.

Maybe even a second poll to pay a couple of bucks extra for pull tabs like on my 88 Supra for removing the rear bottom seat. Instead of laying out 40 bucks to buy two of those plastic holders that break plus your back when trying to remove the rear seat cushion.
 

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Discussion Starter · #9 · (Edited)
UPDATE:

Took the Cruze back in to find out about the fault light. 45 minutes later they called me back to the shop. Sure enough a rodent had made a home on top of the gas tank and not only ate the wires but chewed thru a gas recovery line that IS NOT SERVICEABLE. I got a good look at it up close so I'm sure they weren't making it up. Plenty of rodent poop and bits of wire wrap all over the top of the tank and about 8 holes in the gas vapor recovery line. I asked about wrapping up the line and they said no because it was a safety issue with the gas vapors. The whole tank has to be replaced. WHO THE **** THOUGHT ABOUT MAKING A HARNESS THAT CAN'T BE FIXED !!!!!. $1100 FOR THE TANK PLUS ALL THE LABOR INVOLVED. :sad010: Luckaly they said most vehicle insurance covers this damage under the Non-Collision part of the policy less the deductible. I called the insurance and they are covering it minus $50 which is my deductible. It will take 3 to 5 days but they loaned me a car. Suggested I get some moth balls in a sack to put on top of the tank to chase away the rodents.
 

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UPDATE:

Took the Cruze back in to find out about the fault light. 45 minutes later they called me back to the shop. Sure enough a rodent had made a home on top of the gas tank and not only ate the wires but chewed thru a gas recovery line that IS NOT SERVICEABLE. The whole tank has to be replaced. WHO THE **** THOUGHT ABOUT MAKING A HARNESS THAT CAN'T BE FIXED !!!!!. $1100 FOR THE TANK PLUS ALL THE LABOR INVOLVED. :sad010: Luckaly they said most vehicle insurance covers this damage under the Non-Collision part of the policy less the deductible. I called the insurance and they are covering it minus $50 which is my deductible. It will take 3 to 5 days but they loaned me a car. Suggested I get some moth balls in a sack to put on top of the tank to chase away the rodents.
Wow. Sounds like you have a good dealership as well - they're up front and show you what is wrong.
 

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Discussion Starter · #11 ·
Wow. Sounds like you have a good dealership as well - they're up front and show you what is wrong.
I added a little more to the post but yes, they let me look at the damage up close and told me about the insurance and explained everything I needed to know about the claim.
 
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