Please help..clubgp forum gave me no answer

[Grandprixxgt]

1999 Grand prix gt
Got P0442 code..small evap leak.

1.Changed gas cap
2.Changed evap purge solenoid
3.Vac lines look good..throttle body to fuel pressure regulator...and throttle body to evap purge solenoid.

Cleared code..came back 1 weel later...what next ?

could it be fuel pressure regulator leaking? Carbon canister at back of vehicle? bad fuel pressure sensor?

[Grandprixxgt]

wow nobody here can help me either

[carnutcass]

DTC P0442 Evaporative Emission (EVAP) System Small Leak Detected
Refer to Emmision Hose Routing Diagram, EVAP Control System Overview .

Circuit Description
The evaporative system includes the following components:
- The fuel tank.
- The EVAP vent valve/solenoid.
- The fuel tank pressure sensor.
- The fuel pipes and hoses.
- The fuel fill cap.
- The EVAP vapor lines.
- The EVAP purge lines.
- The EVAP canister.
- The EVAP canister purge valve/solenoid.

The EVAP SMALL LEAK TEST is based on applying vacuum to the EVAP system and monitoring vacuum decay. The PCM monitors vacuum level via the Fuel Tank Pressure sensor input. At an appropriate time, the EVAP purge solenoid and the EVAP vent solenoid are turned on allowing engine vacuum to draw a small vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP purge solenoid is turned off, sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a given time period, all other variables remaining constant. A small leak in the system will cause DTC P0442 to be set.

Conditions for Running the DTC
- No TP sensor, ODM, IAT sensor, or MAP sensor DTCs set.
- The DTC P0440 diagnostic test has passed.
- Startup engine coolant temperature is not more than 4° C and 30° C (40° F 86°F).
- Startup engine is not more than 8° C (14° F).
- Startup Intake air temperature not more than 2° C and 30° C (40° F and 86° F).
- Startup intake air temperature not more than 2° C (4°F).
- Fuel tank level is between 15% and 85%.
- BARO is greater than 75kPa.

Conditions for Setting the DTC
A vacuum decay condition indicating a small leak is detected during the diagnostic test.

Action Taken When the DTC Sets

Important
Although these diagnostics are considered type A, they act like type B diagnostics under certain conditions. Whenever the EVAP diagnostics report that a system has passed, or if the battery has been disconnected, the diagnostic must fail during 2 consecutive cold start trips before setting a DTC. The initial failure is not reported to the diagnostic executive or displayed on a scan tool. A passing system always reports to the diagnostic executive immediately.

- The PCM will illuminate the MIL during the first 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.

Important
Although these diagnostics are considered type A, they act like type B diagnostics under certain conditions. Whenever the EVAP diagnostics report that the system has passed, or if the battery has been disconnected, the diagnostic must fail during two consecutive cold start trips before setting a DTC. The initial failure is not reported to the diagnostic executive or displayed on a scan tool. A passing system always reports to the diagnostic executive immediately.

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 Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for the following conditions:

- Cracked or punctured EVAP canister.
- Damaged source vacuum line, EVAP purge line, EVAP vent hose or fuel tank vapor line.
- Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness. Inspect the wiring harness to the EVAP vent solenoid EVAP purge solenoid and the fuel tank pressure sensor for an intermittent open or short circuit.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:

1-The powertrain OBD System Check promps you to complete some of the basic checks and store the freeze frame and failure records data on the Scan Tool if applicable.

2-If a vent valve or EVAP purge valve electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction that caused the additional DTC to set will very likely correct the condition that set this DTC.

3-Checks for a fuel tank pressure sensor stuck high condition. The fuel tank pressure must be relieved by removing the canister line from the fuel tank or EVAP canister. The fuel fill cap will not relieve the tank due to a check valve in the filler neck. the check valve seals when pressure is applied to prevent vapors from escaping through the filler neck. The Scan Tool should read within +/- 1.0 in. H2O of the specified value.

4-Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes. The EVAP station is pressurizing a sensor that normally reads vacuum. The tech II reads high pressure at 0 volts and high vacuum at 5 volts. The Tech II can only read a max pressure of 6.0 inches of H2O (0 Volts). However the EVAP Service station can pressurize the system to much higher pressures. The Scan Tool value should be within +/- 0.5 of the specified value.

5-Checks for a small leak in the EVAP system.

6-Checks for a leak in the Canister, vent line, or a leaking EVAP Vent Valve.

10-Checks for a leaking or stuck open EVAP canister purge valve/solenoid. The scan tool should read within +/- 1.0 in. HG of the specified value.

16-The EVAP station is pressurizing a sensor that normally reads vacuum. The Tech II reads high pressure at 0 volts and high vacuum at 5 volts. The Tech II can only read a max pressure of 6.0 inches of H2O (0 Volts). However the EVAP Service station can pressurize the system to much higher pressures. The Scan Tool value should be within +/- 0.5 of the specified value.

[GTP Dad]

I would check the charcoal canister that is located in the left wheel well. The canister may be damaged or the lines leading to is may be cracked. If you changed everything else then the problem must lie with the canister. Sometimes they will crack or the filter will become clogged and that will cause your problems. Hope this helps!

[kustomkid54]

Originally Posted by GTP Dad

I would check the charcoal canister that is located in the left wheel well. The canister may be damaged or the lines leading to is may be cracked. If you changed everything else then the problem must lie with the canister. Sometimes they will crack or the filter will become clogged and that will cause your problems. Hope this helps!

Dad,
Isn't that what Cass's says right around step 304. I think you need to go back and read his whole page.

[carnutcass]

Continuation of my last post...........


Step 1
Was the Powertrain OBD System Check performed?
YES - Go to Step 2
NO - Go to Powertrain On Board Diagnostic (OBD) System Check

Step 2
Important:
Visually/physically inspect for the following conditions:

- Vacuum or purge lines disconnected. Refer to Emission Hose Routing Diagram .
- Loose or missing fuel fill cap.

Is DTC P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit or DTC P0449 Evaporative Emission (EVAP) Vent Solenoid Control Circuit also set?
YES - Go to the other DTC first.
NO - Go to Step 3

Step 3
- Ignition switch OFF.
- Remove the EVAP canister line from the EVAP canister purge valve. - This will relieve the fuel tank pressure.
- Ignition switch ON, Engine OFF.
- Observe Fuel Tank Pressure on the scan tool.

Is the Fuel Tank Pressure near 0" H2O?
YES - Go to Step 4
NO - Go to Step 15

Step 4
Important:
Before continuing with diagnosis, zero the EVAP Pressure and Vacuum (inches of H2O) gauges on the J 41413 EVAP Pressure/Purge Diagnostic Station.

Important:
Do not exceed 5" H2O.

- Ignition Switch OFF.
- Reconnect all EVAP hardware that was previously disconnected.
- Install the J 41415-40 Fill Tank Cap Adaptor to the fuel fill neck and fuel fill cap.
- Connect the EVAP Station to the Fuel Tank Cap Adaptor.
- Ignition Switch ON, Engine Off.
- Capture Fail Record data for DTC P0440 and clear DTCs.
- Using the scan tool, EVAP Purge/Seal, select seal option to seal the EVAP System.
- Attempt to pressurize the system to the specified value by slowly turning the EVAP Service Station rotary switch to the "pressure" position. (Monitor the pressure with the gauge on the cart with the rotary switch to the "Off/Hold" position).
- Observe Fuel Tank Pressure on the scan tool.
Is the Fuel Tank Pressure near the specified value of 5" H2O?
YES - Go to Step 5
NO - Go to Step 7

Step 5
Important
Do not exceed 15" H2O.

- Increase pressure to the first specified (higher) value by slowly turning the EVAP Service Station rotary switch to the "Pressure" position. (Monitor the pressure with the gauge on the cart with the rotary switch in the 'Off/Hold position)

Does the EVAP Pressure decrease to less than 10" H2O within 2 minutes with the rotary switch in the "Off/Hold position?
YES - Go to Step 6
NO - Go to Diagnostic Aids

Step 6
- Disconnect the fuel tank vapor line and the EVAP purge line from the EVAP canister.
- Block the canister fitting for the fuel tank vapor line.
- Connect a hand vacuum pump to the canister port for the EVAP purge line.
- Ensure that the EVAP System is still sealed with the Tech II.
- Attempt to apply vacuum to the EVAP canister. The EVAP canister is large and may take time to achieve specified level.

Can vacuum be maintained at 5" Hg?
YES - Go to Step 9
NO - Go to Step 8

Step 7
Visually/physically check for the following conditions:

- Restricted fuel tank vapor line.
- Restricted EVAP purge line.

If a problem is found, repair as necessary.

Was a problem found?
YES - Go to Step 16
NO -Go to DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage

Step 8
Visually/physically check for the following conditions:

- Damaged Fresh Air Vent Hose.
- Damaged EVAP canister .

If a problem is found, repair as necessary.

Was a problem found?
YES - Go to Step 16
NO - Go to Step 13

Step 9
Visually/physically check for the following conditions:

- Leaking fuel tank vapor line.
- Damaged EVAP purge line.

If a problem is found, repair as necessary.

Was a problem found?
YES - Go to Step 16
NO - Go to Step 10

Step 10
- Disconnect the engine vacuum Purge line from the EVAP canister purge valve.
- Connect the EVAP Service Station (Hg) Vacuum Gauge to the Purge Valve/Solenoid, canister side.
- Ignition switch ON, Engine Off
- Using the Scan Tool, EVAP Purge/Seal, Select the seal option to seal the EVAP System.
- Start the engine and idle.
- Run the engine from 1200 -1500 RPM and observe vacuum level.

Is vacuum level near 0" Hg?
YES - Go to Step 12
NO -Go to Step 11

Step 11
Replace the EVAP Canister Purge Valve/Solenoid. Go to Evaporative Emission (EVAP) Canister Purge Valve Replacement .

Is the action complete?
YES - Go to Step 16
NO - WHY THE HELL NOT!!!!!

Step 12
Important
Do not exceed 15" H2O.

- Reconnect all EVAP hardware that was previously disconnected.
- Using the scan tool, EVAP Purge/Seal, select Seal Option to seal the EVAP System.
- With the EVAP pressure/purge diagnostic station connected to the EVAP service port, continuously attempt to pressurize the EVAP system to the specified value by leaving the EVAP pressure/purge diagnostic station control knob in the pressurize position
- Using the ultrasonic leak detector J 41416, locate and repair leak in EVAP system. It may be necessary to partially lower the fuel tank to examine the top tank connections.
- Replace the faulty part(s).

Is the action complete?
YES - Go to Step 16
NO - WHY THE HELL NOT!!!!!
--

Step 13
Replace the EVAP Vent Valve/Solenoid. Refer to Evaporative Emission (EVAP) Vent Valve Replacement .

Is the action complete?
YES - Go to Step 16
NO - WHY THE HELL NOT!!!!!

Step 14
- Check for a kinked or restricted canister purge line between the EVAP canister purge valve and EVAP canister.
- Repair the canister purge as necessary.

Is the action complete?
YES - Go to Step 16
NO - WHY THE HELL NOT!!!!!

Step 15
- Ignition switch OFF.
- Remove the EVAP canister line from the fuel tank or EVAP canister. This will relieve the fuel tank pressure.
- Ignition switch ON, Engine OFF.
Observe Fuel Tank Pressure on the scan tool.

Is the Fuel Tank Pressure near 0" H2O?
YES - Go to Step 14
NO - Go to DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage

Step 16
Important:
Do not exceed the pressure 15" H2O

- Reconnect all EVAP hardware that was previously disconnected.
- Ignition switch On, Engine Off.
- Using scan tool, Purge/Seal, select the seal option to seal the EVAP System.
- Pressurize the system to the first specified (higher) value by slowly turning the EVAP Service station rotary switch to the "Pressure" position. (Monitor the pressure with the gauge on the cart with the rotary switch in the "Off/Hold" position).

Does the EVAP pressure decrease to less than 10" H2O within 2 minutes with the rotary switch in the 'Off/Hold' position?
YES - Go to Step 3
NO - System OK

[kustomkid54]

Now that's long, but it's right. Telling you, if he wasn't so far away, I'd take him for a ride in my car. Might even let him ride in the front.

[GTP Dad]

kustomkid54--To answer your question, Carnutass and I posted close to the same time, when I posted his hadn't even hit the page yet so I was unaware he was going to give such a detailed description when my post was made. Next time don't be so critical of others have to say!

[Grandprixxgt]

ok...now that i need to check the charcoal canister..how do i get it off??? looks like itt might be kinda tough.

[GTPCatz]

charcoal canister?
on a GP?

EDIT:
charcoal canister = EVAP?

[kustomkid54]

Dad, You have to lighten up. I have never said anything bad about any of your post. As a matter of fact, I normally tell people to email you and ask you things. You have to remember that we answer peoples problems with their cars and have a little fun. If we have to stop haveing fun, please let me know now.
Jim

[Grandprixxgt]

um...i really appreciate the detailed explanation of the evap sysytem and how to check it..but i dont have those special scanners to check it...so what would you recommend i check next? or replace?
Im sorry for being so vague about all this but im looking for the easiest way to fix it without going to a dealer and getting screwed.

my car has 98k miles on it so do you think the canister in the back of the vehicle could be shot ??

My evap problem didnt start until after my o2 sensor went...i drove around with a bad o2 sensor for a couple of months.
after i fixed it ses light popped on and it was p0442.

[GTP Dad]

Sorry to come down on you so hard Kustomkid54 but the way you phrased the post was like I didn't pay attention to what was going on. That is far from true as I read every post on the Pontiac forum. Are we still having fun, YES! But some days are more challenging than others.

[carnutcass]

Hey GrandPrixGT, I hate to say it but without the proper test equipment, you're going to be guessing as to what the problem is. I know it sucks paying the dealers high labor rates but think about it, how much will you spend replacing parts by guessing and replacing? Not slamming you man, just trying to offer another perspective.

Dad.......actually, I think Jim was slamming me for posting a 10,000 word post!

Just kidding Jim, you know it's all good.

[kustomkid54]

You know, I think I have said this a couple times in the last few months.
People come on this site to ask about their cars. 99% of the times things get answered. Also guys come on he to vent. And we listen. But, damn we have some fun. We pick on people we know, and some we don't. Most things are asked over and over again, but we still reply. If a thread gets carried away, it happens.
A month ago I seen one thread that was for a joke, and at the start everyone was told it was a joke. Someone put a stop to it. Maybe he didn't like what was being said, Nothing bad was said on it. No dirty pictures, no race, just fun. But this person thought he wanted to push his power. I belong to a lot of other forums. I hear stuff on some of them that would be stopped even in R rated movies. But nun get stopped.
Dad, I wasn't in your case. I thought after Cass gave a 106 page reply, that covered everything, from the 1941 Willeys to today. Your anwser was just too streight. It was right, but you had your spot to shine.
Everyone here is alright, well maybe blurr I worry about. But let's have some fun too,
That was my book for the year.