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'02 Impala: P0440 - Evap Emiss Control Malf


Colt Hero
11-07-2005, 01:29 PM
'02 Impala: P0440 - Evap Emiss Control Syst Malf

'02 Impala, base model, 3.4l engine, bought new, almost 68k miles now. This is the car's first MIL code. Car appears to be running the same as it always has. No idle issues, sufficient power (although I'd swear it's somewhat less than it had new), no pinging, etc. What should I be looking for here? This isn't an obvious one like a bad VSS or CMP sensor such as with my Taurus.

Also, one other issue that very closely preceded this MIL code (and may or may not be related): My message center display had posted a "Low Coolant Level" message just days before. The tank appeared to have sufficient coolant inside when COLD, but I added a little more anyway (full strength because the liquid inside appeared less green then I thought it should have - I've replaced the Dexcool with mixes-with-anything GREEN stuff). It's been over a week now and the message has not reappeared. I know mention of this will raise some red flags about the famous Intake Manifold Gasket problem with these cars, but as far as I can tell, I don't think the problem exists on my car - or, if it does, it's occurring at almost undetectable levels. The car heats up to about 205 degrees (just past mid-scale), and then the fans kick in to knock it back down about 10 degrees. There is no leak near the throttle body, but there IS some dampness on the other side of the block along the V-Seal behind the Serpentine Belt. The oil on the dipstick looks and smells OK, but there IS a greasy film inside the plastic coolant tank, and I HAVE seen some fudgicle sludge on the radiator cap and filler neck (which I've wiped out a couple of times).

Questions:
1.) Any insights on the P0440 code?
2.) Any connection between the code and the Low Coolant Message?
3.) Are there any chemical tests to detect coolant in engine oil?
4.) How does this car detect a Low Coolant Level? I know it has a Coolant TEMP sensor, but I don't see a LEVEL sensor. There isn't one on the plastic recovery tank...

maxwedge
11-07-2005, 02:03 PM
I hope you got all the dex out any intermix can cause problems. P0440 is a evap malfunction, you will need a bi directional scanner to check this out properly. Look for any disconnected or cracked hoses anywhere in the evap system from the cannister to the engine compt and tank, first.

BNaylor
11-08-2005, 12:48 PM
Questions:
1.) Any insights on the P0440 code?
2.) Any connection between the code and the Low Coolant Message?
3.) Are there any chemical tests to detect coolant in engine oil?
4.) How does this car detect a Low Coolant Level? I know it has a Coolant TEMP sensor, but I don't see a LEVEL sensor. There isn't one on the plastic recovery tank...

P0440 is either a large or moderate leak in the evaporative emissions system. Engine vaccum is applied to the system and then it is monitored for decay over a period of time. The PCM uses the fuel tank vacuum sensor to accomplish this. At a predetermned period of time, the EVAP PURGE solenoid and EVAP VENT solenoid are turned on. Whenever a sufficient vaccum level is not achieved, the PCM will set P0440 which is specifically a large leak or faulty EVAP PURGE solenoid.

I agree with Max on the part where you need to check all the vacuum hoses associated with the evaporative emissions system. Also the fault can be caused by a defective gas cap.

Your coolant level sensor is probably located on the passenger side of the radiator engine side about 4" below the radiator filler neck similar to other GM "W" bodies. On other 3.4L like the Malibu, Alero and Grand Am it is located on the plastic coolant tank.

MoNsTeR`ImPaLa
11-08-2005, 12:58 PM
did you get the upgraded intake gasket issued by GM there have been cases of the dex cool eating the gasket that cam stock in the 3.4's

search this forum you find more info

spacemoose39
11-08-2005, 09:00 PM
Damn, i didnt get this much love when i asked about a 440!

Anywho, any chance that a 440 could be cause by a faulty Air intake temperature sensor?

Ive been getting the shitties of milage as of late and do not know what to do.

BNaylor
11-09-2005, 08:39 AM
Damn, i didnt get this much love when i asked about a 440!

Anywho, any chance that a 440 could be cause by a faulty Air intake temperature sensor?

Ive been getting the shitties of milage as of late and do not know what to do.

What size engine do you have in your Impala?

It's possible although unlikely. However, the engine coolant temperature sensor (ECT) and intake air temperature (IAT) sensor are referenced during startup when evaporative emissions leak detection is run by the PCM. But in order to generate DTC P0440 one condition is there are no IAT sensor DTCs set but a bad IAT doesn't necessarily give a DTC error code. Is P0440 the only obd-ii DTC showing on your scanner. What type of mileage are you complaining about?

ogre73
11-10-2005, 01:10 PM
...the engine coolant temperature sensor (ECT) and intake air temperature (IAT) sensor are referenced during startup when evaporative emissions leak detection is run by the PCM. But in order to generate DTC P0440 one condition is there are no IAT sensor DTCs set but a bad IAT doesn't necessarily give a DTC error code.

FYI: Other conditions are that no MAP, TPS, VSS, ECT, Vacuum Sensor, Purge Solenoid, Canister Vent, or Thermostat Rationality DTCs be set. There are other parameters as well. See page 34 of the .pdf file in the third link here (for your 2002) http://www.automotiveforums.com/vbulletin/showthread.php?t=454260 .

Jim

ogre73
11-10-2005, 01:22 PM
'02 Impala: P0440 - Evap Emiss Control Syst Malf

Questions:
1.) Any insights on the P0440 code?
I have the same code. Mine was preceeded by a P0444 (see this thread) http://www.automotiveforums.com/vbulletin/showthread.php?t=399169 . I have yet to solve the issue. I tried a new gas cap but got no love there. I think the next thing I will do is get a new Purge Control Valve, as they are only about twenty bucks. After that, I may need to get a smoke test done. This is where they put special smoke in your system at less than 1 psi (to avoid damage to sensitive parts) and they look for a leak.

2.) Any connection between the code and the Low Coolant Message?
Not likely. There are a lot of things that are connected, but that wouldn't likely be connected to this problem unless you did physical damage to both systems at the same time somehow.

3.) Are there any chemical tests to detect coolant in engine oil?
There must be, but they may be expensive if you are trying to get quantitative data. There may be something cheap to tell you if there is any at all, but there may be a trace amount and not affect your car.

Jim

spacemoose39
11-10-2005, 01:34 PM
What size engine do you have in your Impala?

It's possible although unlikely. However, the engine coolant temperature sensor (ECT) and intake air temperature (IAT) sensor are referenced during startup when evaporative emissions leak detection is run by the PCM. But in order to generate DTC P0440 one condition is there are no IAT sensor DTCs set but a bad IAT doesn't necessarily give a DTC error code. Is P0440 the only obd-ii DTC showing on your scanner. What type of mileage are you complaining about?


My impala has a 3.8L engine.

Yes, 440 is the only code im showing. I used to have a 442, but that was rectified when i changed my fuel cap.

Milage? well. I used to get around 475Kilmoeters before the low fuel light would activate, now its like 380k and its on. Its really starting to bother me!

BNaylor
11-10-2005, 03:06 PM
My impala has a 3.8L engine.

Yes, 440 is the only code im showing. I used to have a 442, but that was rectified when i changed my fuel cap.

Milage? well. I used to get around 475Kilmoeters before the low fuel light would activate, now its like 380k and its on. Its really starting to bother me!

That's a significant drop in mileage from 475K to 380K. We sold our '01 Impala LS earlier this year for reasons I won't elaborate on and we never got below 340 miles on 17 gallons in city. On the highway we were hitting 27 mpg (460 miles). I could make it all the way to Phoenix from El Paso.

380K = 236 miles
475K = 295 miles

Out of curiosity are you sure the vaccum lines are routed correctly and tight, especially around the UIM/throttle body to the evap. purge solenoid and to the rear evap vent solenoid? If you have access to one, try running a vacuum test with an automotive vacuum gauge. It should read around 15" hg and steady. You can tee into the line feeding the purge solenoid or fuel pressure regulator.

spacemoose39
11-10-2005, 03:42 PM
That's a significant drop in mileage from 475K to 380K. We sold our '01 Impala LS earlier this year for reasons I won't elaborate on and we never got below 340 miles on 17 gallons in city. On the highway we were hitting 27 mpg (460 miles). I could make it all the way to Phoenix from El Paso.

380K = 236 miles
475K = 295 miles

Out of curiosity are you sure the vaccum lines are routed correctly and tight, especially around the UIM/throttle body to the evap. purge solenoid and to the rear evap vent solenoid? If you have access to one, try running a vacuum test with an automotive vacuum gauge. It should read around 15" hg and steady. You can tee into the line feeding the purge solenoid or fuel pressure regulator.


Oh man.... I appreciate your reply and your willingness to help, but that is allllll french to me!

Perhaps a trip to a chevy shop is in order?

The milage has been getting slightly better with the instalation of my new intake system. I removed the stock air box..yadda yadda yadda im sure we all know how that one goes.

One thing im wondering is tho, can the "bottom" part of the air box be safely removed? I noticed some electrical components attatched to it and dont wana really do any major screwing around.

BNaylor
11-10-2005, 06:48 PM
Oh man.... I appreciate your reply and your willingness to help, but that is allllll french to me!

Perhaps a trip to a chevy shop is in order?

The milage has been getting slightly better with the instalation of my new intake system. I removed the stock air box..yadda yadda yadda im sure we all know how that one goes.

One thing im wondering is tho, can the "bottom" part of the air box be safely removed? I noticed some electrical components attatched to it and dont wana really do any major screwing around.

No problem. I agree unless you have tools like the vacuum gauge and the GM service manual which has the proper troubleshooting procedure you're probably better off taking it to the dealer's service dept. With a Tech II machine, they should be able to find the problem rather quickly. No need to guess, procrastinate or replace parts that may not fix the problem. On the part of the air box with the electrical harnesses that's all connected to the Powertrain Control Module (PCM) located in that housing.

Good luck and hope you get it fixed.

luminacrazy
02-11-2008, 07:51 PM
I have an 02 Impala LS and have the same 0440 code. I was at the dealer the other day and I saw that the dealer service department are doing a land office business replacing Vent Solinoids part # H15208329. I replaced the gas cap and got some love for about a month and then the code reappeared. Is it worth the chance at replacing the vent solinoid, it would appear so since the dealer charges $40.00 to do a diagnostic? Any ideas from someone with a similar experience?

maxwedge
02-12-2008, 03:42 PM
2 year old thread here, start a new one please.

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