Chevy S-10 Blazer poping code PO452

MADMAN

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#1
Please let me thank all in advance for what ever help you can give me, THANK YOU! Now, i have a 2000 Chevy Blazer (S-10 style) 4.3 engine with 132XXX on the odometer, automatic, 4 wheel drive, 4 door that just started showing a PO452 code. car ran fine to work, came out and started it up, while i cleaned off the snow and frost (since we reside in the chicagoland area and temps were in the teens this morning) and got back in, i noticed the mil on. car starts fine, runs fine, no ping, or detenation noises. checked it at home and had the code PO452, 2 times? I used a INNOVA 3100C hand held code retriever. 1st code came up as the priority code and same code came up a second time as a pending code. i cleared the codes, took car for a ride, and in 5 seconds it came up again as a pending code PO452. I know this is part of an emmisions code, some were in the tank purge? or venting? according to code book. but any help to pinpoint the exact problem? I have no idea were the charchol tank is at, i dont see it under the hood anywere. thanks again
 

nickb2

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#2
Fuel pressure sensor code. Here is a PDF you can download for diagnostic use.

[attachment deleted by server]
 

MADMAN

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thanks nickb2, but i'm a bit confused on this one? In the step: DIAGNOSTIC AIDS
1. Inspect the control module harness connectors for the following conditions:
^ Improper mating
^ Broken locks
^ Improperly formed
^ Damaged terminals

Are they refering to the in tanks module? the one that holds the fuel pump, and sending unit? is this were the fuel tank pressure sender is? we replaced the fuel pump unit about 2 yaers ago, never had a problem from then on. and as far as wiring goes, it was all color coded, as i mateted the wires they were soldered very well and heat shrink, with taping them into a new loom. i hate to have to drop the tank again to test the wires if thats were its at? thanks
 

nickb2

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#4
On top of fuel pump unit, should be able to get to it without removing tank for connector, as for removing, maybe just lowering the tank will do. A picture is a thousand words, here it is,

[attachment deleted by server]
 

MADMAN

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#5
OH MAN, I really hate to drop that thing again, i remember messin with it 2 years ago. but if thats were its at, then i guess maybe it can wait to a warmer day, like in may! any other posabill reasons this code will set. i noticed a electrical connection with a "PRESSURE SENSOR" up on the intake manifold, near the coil and throttle body that says pressure sensor on it, any idea what this one is? and can the canister be at fault? are those filters still replaceable? thanks
 

nickb2

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#6
You DON'T want to be messing with that other pressure sensor!! That one is the MAP sensor. Manifold absolute pressure sensor. This sensor will affect your engine and driveability. As for canister, no relation to your code. They are both part of the emission control systems but operate on different circuits. The canister vent valve, purge valve and others will set a proper code to those circuits such as a small - gross leak detected. A busted canister or evap system leak would set a small - gross leak detected code. In principle a fuel pressure sensor malfunction will not cause a serious concern in driveabilty but it will mask any other codes that may affect engine as evap codes are always set as priority due to emissions laws.
 

MADMAN

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Thanks nick, i believe i just about tryed everything, i checked all the lines and hoses for leaks, no damaged from tank to canister, (if thats the one mounted behind rear fender well right side) visual check for any bad hoses, or tubing to engine, droped tank to get to connector, no visual cgreen gooo, or corrosion, untaped all wires, peeled of all heatshrink, and wires look as good as the day i put in new pump module. i still had old module and since old pressure sensor was still on it, i swaped them out (never a problem with this code when older module was in) cleared codes, and still poped the PO452, 2 times again, just a few seconds after car started up. Can you tell me which wires at the conector is the one to check for 5 volts, and which one is the ground? before i jump (test) for voltage and short everything out, thanks
 

billr

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#8
Since this thing is monitoring pressure in the tank, how about the gas-cap and tank fill pipe? If either of them were leaking , then I would think the same code would be set. At the gas-cap, make sure the cap seal is OK and check the mating metal surface in the pipe for rust/pitting.
 
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#9
I had that code pop up a couple of times, and couldn't find anything wrong, PCM gets bored and runs a fuel evaporative emission test. And the two times it popped up was on very cold damp days. Major cure was to park my vehicle in a heated garage so it could dry out and if you happen to be using ethanol based fuels that gathers moisture, sure doesn't help.

When the vehicle is parked, one valve opens permitting gas tank pressure to release through the charcoal canister, have to do that or else with the heat of the day, the tank would explode due to fume expansion. When the engine is running, another valve opens to purge the canister to burn that fuel. At this time, that pressure switch should be showing a minor vacuum. But it can't do that if there are any leaks in the fuel system, such as the gas cap as already suggested, or it can be that pressure sensor itself.

Or even the vent valve, on my vehicle, the purge valve is located on top of the engine where it can dry out, but some stupid idiot mounted that vent valve clear back at the tank with the canister, must have been smoking crack at the time or just plain stupid where the canister and the vent valve is subject to all that salt crap they put on the roads. Or you could be pouring moisture in your tank when you are paying $3.40 a gallon for it. If my vent valve was the culprit, didn't show up after I pulled it and placed it on my warm work bench where it could dry out and pass a perfect vacuum test when closed.

I check all the connections, they were clean, so I figure moisture was the problem, put it all back together and that code never came back until another cold damp day. That time, just turned on the heat in my garage and left it, code went away on its own.

Wouldn't have these kind of problems with the vehicle sitting in a warm and air conditioned showroom. Should have left it there.
 

MADMAN

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#10
thanks again all. its been awhile here in the cold and i couldnt do much to it because of health, but i did talk nicely to a employee here at illinois air testing station, and he rechecked my gas caps (i changed to a locking style, and the original one) both checked out good! so going on the idea it might be just some ice, or a frozen pressure sensor, or one of the valves, i decided to leave it alone till it got warmer. todays temps reached 37, wow a heat wave! so we went out and tryed to clear the codes and see what happends. before i keeped getting 2 codes, 1. P0452 as a solid code, ad a P0452 as a pending code, today i got 3 codes 1. P0452 (solid) 2. P0453 (solid) 3. P0453 (pending) now its reading high pressure ????? how can it read low pressure, then high pressure, both at the same time? sounds maybe its is the pressure sensor, or wiring? any help or thoughts, thanks guys!
 
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#11
Not much different than your home computer with a problem, is it hardware or software causing it to go crazy? You can manually check out the hardware, vent and purge valves sealing properly when closed, solenoids for operation, pressure sensor for accuracy, canister not blocked, wiring and connections all good and find nothing wrong. Leaving the possibility that the software is corrupted, how many times do you have to reload Windows to solve a problem?

Your vehicle is not much different, but the code is stored in flashram much like your digital camera, claim the life of retaining code in a flashram is ten years, you are already past that stage, could be your code is corrupted. This adds another complication to doing maintenance as your vehicle may need to be reflashed. Last time I checked with my dealer on this subject, he would do it for 80 bucks, need a GMTech II scanner, a suitable notebook computer, and most important, the firmware not generally available to the public. They don't give you a disk when you purchase a vehicle.

This is just another possibility why you can get weird readings.
 

MADMAN

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#12
I always woundered why things sometimes (pert near always) seem to be differcult to me. I never did check out complettly the "HARDWARE" i just check the hoses and connections cause i didnt know which wires are ground hot or a low voltage. and under hood sticker shows the ( i believe its the purge valve or the solenoid) is supposed to be mounted there? but as i asked before the one that said sensor on it, the other nick told me "DONT TOUCH THAT ONE" so i'm not to sure wich one is the purge valve and which is the solenoid? and i didnt see anything mounted it the rear (left side (drivers side)) behind the tire where the canister appears to be except for the canister and some lines, which all apeared to be fine. so i'm lost for now. And to make things wrose their calling for colder temps, and lots of white powder to fall in the next couple of days. working in the apartment complex parking lot is a drag, and with my health problems, its hard to get out and play with it. So thanks to all, and as soon as i can play with it it again i reply back to maybe help some one else. anybody got any infor on where all this valves and solenoids are mounted, hate to start a guessing game parts do get costly. i do not have a fancy scanner, just a code reader, and trying to avoid a costly trip to a shop or dealer. Got way to many doctor and hospital bills right now, but i do know those that do this for a living, need guys like us for their income and families. But thanks to all for the help again! thanks
 

nickb2

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#13
Purge valve (#4) right below the MAP sensor, The one I said not to touch.
#7 in second picture.
Now depending on if this is a four door or a 2 door, the Evap vent valve is located above the spare tire. Lower the tire to access it on 4 door.
2 door it is same but there is a shield you must remove. Is there anything else you need MADMAN? And if you can do it yourself, why not. No skin off my back when some guy can fix his own car. In my area these types of repairs relating to EVAP systems are ignored due to NO emission laws anyways.

[attachment deleted by server]
 
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#14
Can appreciate living in an apartment with signs all over, no working on vehicles, doctors inflated fees are outrageous, what cost five bucks 30 years ago, today costs 500 bucks. City just opened an assisted home with 62 rooms, claim it cheaper than a nursing home, but have to be well enough to use the rest room and take a shower that is in each room. Don't get it, if you can do that, can also make your own food, no medical insurance covers it, and the price per room, mostly dependent on the view you get looking out the window is between 3,500 and 6,500 bucks per month. Told me that was cheap. Took a tour of the place, but felt like I was in a prison. After two months, all the lights are out at night, so offering 30 days free now.

Diagnostic systems are purely electronic, no help if a bumper falls off, if the CEL is coming on the instant you turn on the ignition. More than likely an open or a short in the sensors or solenoids, shorts blow out fuses or cause smoke, more than likely an open circuit. Would be nice if your PCM reports over your radio, a fuel evaporative test is going to be made, damned cars don't tell you nothing. Just turn on that damned heart attack light. Call that HAL for short like that insane computer in that movie. Typically the fuel evaporative test is conducted when the vehicle is warm and driving steady on the highway. So when that damned light comes on, give you a hint to what to look for.

When I first saw that GM was mounting the spare under the vehicle, really thought that was dumb, 99% of the time so rusted with road salt, can't even get the damned thing off, son wanted to buy one, said okay, but don't bring it here. Very good spot to mount the vent valve, a wonderful spot for all kinds of debris to built up. More than likely a corroded connector, see a lot of that with crap spread all over under the vehicle constantly exposed to road salt along with rusted out brake and fuel lines plus the parking brake cables. Should of left the damn thing in the showroom where it is protected. Then all the fancy carpeting with no place to wipe your feet.

What's wrong with touching your purge valve, like you wife, kids, and pets, screaming for attention. Took mine off, cleaned it, poured some denatured alcohol to soften the neoprene, tested with on the bench with a 12 V power supply and a hand vacuum pump, and it smiled back at me, it wanted attention. Everything wants attention, enough to drive you nuts and spread you paper thin. Probably wouldn't be to concerned with a fuel evaporative code, as long as 3.50 a gallon of fuel isn't being spilled and the vehicle still runs well. If the EPA is so concerned about HC's in the air, should do something about the millions of tons of methane the earth releases into the atmosphere. A known six thousand year supply of that stuff that could solve all of our energy problems if we had a vehicle that could run on it.

But that is the way our government is, picking on the insignificant stuff. Okay to have an ethanol plant killing everyone that lives near it, but light a candle, and they are screaming at you.
 

nickb2

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#15
@NickD I figure you may want to make one of these for your cavalier. :ROFL That's one hell of a methane usage. Wonder if this thing has EVAP system diagnostics on board!! :eek:
Check it out here. Turn up your sound system if your hooked up from your computer to a sub-woofer. Very impressive use of fossil fuel. :thx
http://www.liveleak.com/view?i=670_1295637159
Notice at the end of the video, see how clean that sucker burns and cools right off. I just can't get enough of seeing that video. Wonder what a 1/4mile would look like with that strapped to a funny car.