I have a 97 3.8Liter that was originally throwing two p0441 codes. I replaced the gas cap with an oem cap and that took care of one code. For the last few months its been reading one p0441 evap code (incorrect purge flow). While driving the car you can hear a vacuum leak, and my mass air flow sensor was compensating for the leak. So I searched for a vacuum leak and found a disconnected vacuum hose in my evap canister(which is located in the driver side rear wheel well). I cant figure out were the hose is supposed to be connected. I just wanted to see if anyone had a vacuum diagram of the evap canister, or if anyone has any knowledge on this topic. Any help would be greatly appreciated.

 

im pretty sure its not suppose to have anything connected to it, check under the hood there is a wiring diagram

 

He's not needing a wiring diagram, but a vacuum diagram.

In my '96, there are three hoses that come out of that canister.

One follows the fuel lines all the way to the engine, at which point it meets the purge vent switch and the purge solenoid before going to the TB.

The other two (if I'm not mistaken) both lead to the gas tank. It's like a send and recieve line for the extra vapors. One of these has a directional valve as well.

All three of those hoses travel through the little hole that the fuel filler tube travels down. You can see them from below if you look up past the gas tank.

At what point is it disconnected? Is there a hose attached to the canister but open on the other end? or is it a connection at the canister that has no hose attached? Which of the three connections on teh canister is in question? That would help me give better instruction on where it should lead.

 

there are two hoses that lead to the top of the gas tank i believe, and the third hose is about a foot long and leads no where. It appears it has been cut or disconnected from somewhere. I had the fuel pump replaced at a shop, they may have cut the line while droppin the gas tank, and did not reconnect it.

 

Does one of your two lines that IS connected have a directional valve about a foot down the tube? If not, that's where this disconnected line should go. Prop the back side up on some jack stands, and look up from below. See if there's a hose under there that has a valve on the end of it.

If one of your connected lines DOES have this valve connected, look under the car and locate your fuel filter. It should be right near that wheel, on the left side of the car. There are two fuel lines there, along with a third hose (vacuum, usually plastic). Follow that vacuum line towards the back of the car, and see if it connects at the end. That line should connect directly to the canister.

 

the three hoses coming from the evap cannister (including the hose with the directional valve) are connected to the top of the gas tank. As well as the vacuum hose and two fuel lines coming from the engine. The hose that is not connected to anything is the middle hose on the evap cannister. All other vacuum hoses seem to be connected properly, its really starting to become annoying that i cant figure out were this middle hose on the evap cannister connects too. If you know off the top of your head where the middle vacuum hose coming out of the evap cannister goes it would be appreciated. Thanks nnewquist you've been a great help.

 

I don't know off the top of my head. It's been a while since I've been under there (I had to replace my canister a while back). If I get a chance tonight, I'll look and follow the hoses to see where that middle one is supposed to go.

If this has been happening ever since you got your fuel pump replaced, I'd take it back to those folks and tell them they didn't reinstall everything properly. Make them fix it, since they messed it up. If it's any kind of respectable place, they'd do it at no charge.

 

Here ya go:


Document ID# 48949
1997 Chevrolet/Geo Camaro
DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge

Circuit Description

The EVAP purge solenoid valve allows manifold vacuum to purge the canister. The Powertrain Control Module (PCM) supplies a ground to energize the EVAP purge solenoid valve (purge ON). The EVAP purge solenoid control is Pulse Width Modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. The duty cycle is calculated by the PCM and the output is commanded when the appropriate conditions have been met:

* Engine coolant temperature above 25°C (77°F).
* After the engine has been running about 2 1/2 minutes on a cold start or 30 seconds on a warm start.
* The vehicle is operating in closed loop fuel control.

Canister purge commanded duty cycle varies according to operating conditions determined by mass air flow, fuel trim, and. intake air temperature. Canister purge will be disabled if TP angle increases to above 70%. Canister purge will be re-enabled when TP angle decreases below 66%.

The EVAP purge vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge solenoid. The EVAP purge vacuum switch will open when vacuum increases to greater than 5 inches of water in the purge line. The PCM monitors the EVAP purge vacuum switch signal to determine of the evaporative emission control system is working properly. If the switch is closed (no purge flow) when the PCM is commanding the EVAP purge solenoid ON, DTC P0441 will be set.
Conditions for Setting the DTC

* No EVAP Vacuum Switch, TP sensor, IAT sensor, Idle Speed, MAP sensor, or EGR DTCs set.
* BARO reading is greater than 70 kPa.
* Engine Coolant Temperature is less than 114°C (237°F).
* Intake Air Temperature (IAT) sensor indicates an ambient temperature less than 70°C (158°F).
* The difference between ECT and IAT is less than 10°C (18°F).
* Engine speed is between 550 rpm and 5000 rpm.
* TP Sensor Indicates throttle position between 2.5% and 52%.
* Manifold vacuum is greater than 10 kPa.
* Canister purge PWM is greater than 75%.
* EVAP vacuum switch remains closed (12 volts signal at the PCM).
* Above conditions for longer than 4 seconds.

Action Taken When the DTC Sets

* The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
* The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC

* The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
* The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
* The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

* Poor connection at the PCM - Inspect harness connectors for the following conditions:
o Backed out terminals.
o Improper mating.
o Broken locks.
o Improperly formed or damaged terminals.
o Poor terminal to wire connection.
* Damaged harness Inspect the wiring harness for damage
* If the harness appears to be OK, observe the EVAP vacuum switch display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.
* Faulty or damaged canister A faulty canister may intermittenly allow charcoal into the EVAP purge solenoid, vacuum switch, and associated lines causing a DTC to be set. Use the following procedure to check for a carbon release condition:
1. Turn OFF the ignition switch.
2. Remove the EVAP purge solenoid. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid .
3. Remove the EVAP vacuum switch. Refer to Evaporative Emission (EVAP) Vacuum Switch .
4. Lightly tap the purge solenoid and (if applicable) the vacuum switch on a clean work area looking for carbon particles exiting either of the vacuum ports.
5. If no carbon release is evident, reinstall the components and continue with the DTC P0441 diagnostic table. If carbon is being released from either component, continue with this service procedure.
6. Remove the EVAP Canister from the vehicle. Refer to Evaporative Emission (EVAP) Canister Replacement
7. Ensure that the main cylinder valve is turned off on the J 41413 EVAP purge/pressure diagnostic station.
8. Disconnect the black hose that connects the nitrogen cylinder to the EVAP purge/pressure diagnostic station at the pressure regulator by unscrewing the knurled nut on the regulator. No tools are required to remove the black hose from the regulator.
9. Using a section of vacuum line, connect one end over the open threaded fitting of the EVAP purge/pressure diagnostic station pressure regulator.
10. Connect the remaining end to the purge solenoid end of the EVAP purge line at the vehicle and turn on the main nitrogen cylinder valve. Continue to blow any debris from the purge line for 15 seconds.
11. Return the EVAP Pressure/Purge Diagnostic Station to its original condition by re-installing the black hose that was disconnected in step 8.
12. Replace the following components:
o Replace the EVAP purge solenoid. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid .
o Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
o Replace the EVAP vacuum switch. Refer to Evaporative Emission (EVAP) Vacuum Switch .
13. Proceed with the DTC P0441 diagnostic table.

Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

19.

This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

Step


Action


Value(s)


Yes


No

1


Was the Powertrain On-Board Diagnostic (OBD) System Check performed?


--


Go to Step 2


Go to the Powertrain On Board Diagnostic (OBD) System Check

2


1. Select output controls, EVAP purge solenoid on the scan tool.
2. With the engine idling, observe EVAP Vacuum Sw.on the scan tool.
3. Command the EVAP purge solenoid ON with the scan tool.

Does the EVAP Vacuum Sw. display Purge with the EVAP purge solenoid commanded ON?


--


Go to Step 3


Go to Step 4

3


1. Review and record scan tool Fail Records data.
2. Operate the vehicle within Fail Records conditions.
3. Using a scan tool, monitor Specific DTC info for DTC P0441 until the DTC P0441 test runs.

Does the scan tool indicate DTC P0441 failed this ignition?


--


Go to Step 4


Refer to Diagnostic Aids

4


1. Disconnect the purge line to the canister at the evap vacuum switch.
2. Plug the purge line fitting at the evap vacuum switch.
3. With the engine idling, observe EVAP Vacuum Sw. on the scan tool.
4. Command the EVAP purge solenoid ON with the scan tool.

Does the scan tool display Purge?


--


Go to Step 5


Go to Step 6

5


Check the purge line to canister for damage or improper connections.

Was a problem found?


--


Go to Step 20


Go to Step 14

6


1. Turn OFF the ignition switch.
2. Install a vacuum gauge between the EVAP purge solenoid and the Vacuum Switch.
3. With the engine idling, command the EVAP purge solenoid ON with the scan tool.

Does the vacuum gauge indicate vacuum greater than the specified value?


12 in. Hg


Go to Step 7


Go to Step 8

7


1. Turn OFF the ignition switch.
2. Disconnect the EVAP vacuum switch electrical connector.
3. Turn ON the ignition switch.
4. Observe EVAP Vacuum Sw. on the scan tool.

Does the scan tool display Purge?


--


Go to Step 15


Go to Step 9

8


1. Turn OFF the ignition switch.
2. Install the vacuum gauge in the source line to the EVAP purge solenoid.
3. Engine idling, observe the vacuum gauge.

Does the gauge indicate vacuum greater than the specified value?


12 in. Hg


Go to Step 10


Go to Step 16

9


1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Turn ON the ignition switch.
4. Check for a short to voltage in the EVAP vacuum switch input circuit.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Electrical Diagnosis.

Was a problem found?


--


Go to Step 20


Go to Step 19

10


1. Turn OFF the ignition switch.
2. Disconnect EVAP purge solenoid electrical connector.
3. Connect a J 34142-B Unpowered Test Light between the EVAP purge solenoid connector terminals.
4. Turn ON the ignition switch.
5. Using the scan tool, command the EVAP purge solenoid ON.

Is the test light ON?


--


Go to Step 17


Go to Step 11

11


1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Connect a test light between the EVAP purge solenoid connector terminals.
4. Turn ON the ignition switch.
5. Jumper the EVAP purge solenoid driver circuit to ground at the PCM connector.

Is the test light ON?


--


Go to Step 12


Go to Step 13

12


Check for a poor connection at the PCM.

Was a problem found?


--


Go to Step 20


Go to Step 19

13


1. Locate the EVAP purge solenoid wiring problem. Check for the following conditions:
* EVAP purge solenoid ignition feed circuit open or shorted to ground.
* EVAP purge solenoid driver circuit open.
2. Repair faulty circuit as necessary. Refer to Wiring Repair in Electrical Diagnosis.

Is the action complete?


--


Go to Step 20


--

14


Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .

Is the action complete?


--


Go to Step 20


--

15


Replace the EVAP vacuum switch. Refer to Evaporative Emission (EVAP) Vacuum Switch

Is the action complete?


--


Go to Step 20


--

16


Locate and repair the cause of no vacuum.

Is the action complete?


--


Go to Step 20


--

17


1. Check for a poor connection at the EVAP purge solenoid.
2. If a problem is found, repair as necessary. Refer to Wiring Repair in Electrical Diagnosis.

Was a problem found?


--


Go to Step 20


Go to Step 18

18


Replace the EVAP purge solenoid. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid

Is the action complete?


--


Go to Step 20


--

19


Replace the PCM.

Important:

The replacement PCM must be programmed. Refer to PCM Replacement/Programming .

Is the action complete?


--


Go to Step 20


--

20


1. Review and record scan tool Fail Records data.
2. Clear DTCs.
3. Operate the vehicle within Fail Records conditions as noted.
4. Using a scan tool, monitor Specific DTC info for DTC P0441 until the DTC P0441 test runs.

Does the scan tool indicate DTC P0441 failed this ignition?


--


Go to Step 2


System OK
Document ID# 48949
1997 Chevrolet/Geo Camaro

 

Also:

Document ID# 824194
1997 Chevrolet/Geo Camaro
Info - Evaporative Emissions DTC P0440, P0441, P0442, P0446 #00-06-04-011A - (Oct 4, 2001)
Evaporative Emissions DTC P0440, P0441, P0442, P0446

1996-2002 Passenger Cars and Trucks

With Enhanced Evaporative Emissions Engines

Except 1998-1999 Chevrolet Prizm

This bulletin is being revised to add model years and diagnostic enhancements. Please discard Corporate Bulletin Number 00-06-04-011 (Section 6-Engine).

Enhanced Evaporative Emissions testing of 1996 and newer vehicles with enhanced evaporative emissions requires more stringent testing of the fuel system for evaporative emissions leaks. Vehicles with this system use an on-board diagnostic module (i.e. Powertrain Control Module (PCM) or Vehicle Control Module (VCM) as the controller. For the balance of this bulletin, we will refer to either of these components as a module.

Enhanced Evaporative Emission tests may be performed by the vehicle's module when specific conditions are met. These conditions are determined by the calibration within the module. These calibrations are vehicle platform and engine family specific.

When the key is turned to the start or run position, the module checks the output of various sensors on the vehicle to determine when and if the Evaporative Emissions tests should be run. Refer to Engine Controls sub-section of the appropriate Service Manual for specific DTC information.

Some of the most widely used parameters are listed below:

1. The Barometric Pressure (BARO) is greater than a specified kPa (psi).
2. The system voltage is between 10 and 18 volts.
3. The intake air temperature (IAT) is within specified temperature values.
4. The engine coolant temperature (ECT) is within specified temperature values.
5. The ECT and IAT are within specified temperatures of each other when the vehicle engine was started.
6. The fuel level sensor indicates the fuel level is greater than a specified % of empty and less than a specified % of full. (For a 76 L (20 gal) fuel tank, a fuel level of more than 11 L (3 gal) but less than 64 L (17 gal) or as specified in the calibration).
7. Some platforms such as the Alero and Grand Am, use a miles driven check as well.

For the ECT and IAT to be within the specified temperatures of each other at the time of engine start-up, the engine will have to be in the non-running condition for a long enough period of time for the engine coolant temperature to drop from its normal operating temperature down to roughly 30°C (90°F). This could take several hours.

When the control module determines that the above conditions are met, the module tests for a leak in the EVAP system by:

* Electrically closing the vent valve in order to seal the system.
* Electrically opening the purge valve which allows the running engine to draw a vacuum on the fuel tank.
* The module then closes the purge valve, resealing the system.
* The module then monitors the fuel tank pressure sensor and determines:
o If vacuum was achieved.
o If a leak is present, how large the leak is.
o If vacuum was not achieved.
* If one of the above tests fails, the module remembers that the system failed the test.
* If the module sees a failure of the EVAP test for two consecutive tests, the module will set a trouble code for EVAP leak (DTCs P0440, P0442, or P0446).

Important

If the PCM is completing the EVAP diagnostic, filling of the fuel tank cannot be completed as the vent valve will be closed and the fuel dispenser nozzle will sense the pressure build-up and shut down. This is the expected result. No parts should be replaced as nothing is faulty. To keep from encountering this situation, it is imperative all customers and dealership personnel be advised NOT TO FILL THE FUEL TANK WITH THE ENGINE RUNNING. If the condition is encountered, turn the ignition to the OFF position for a minute. This will allow the PCM to go to sleep completely, thereby opening the vent valve.


GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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I didn't have a chance to get under my car last night, but I found this diagram:

http://www.fixya.com/uploads/Images/011CD55.gif

It looks like one of the hoses on the canister should be open to the atmosphere, just like one of the hoses on the purge valve is.

There's a pressure valve (diaphram type) inside the canister that basically attempts to equalize the pressure outside the canister and the gas tank pressure. If that valve is busted, it would cause a vacuum leak that would lead to the engine sucking in clean air from that canister. If that's the case, you need to replace the canister.

Another thing that could cause a vacuum leak at this canister is if the valve between the gas tank and the canister is on backwards.

When you said that you heard a vac leak, where did you hear it? Under the hood or behind that wheel? It's possible that some of the rubber connectors for those plastic pipes that run under the vehicle have deteriorated (I had to replace every single one of them on my car).