My 02 ZO6 threw a CHECK ENGINE LIGHT (CEL) on the way to work this morning. OH GREAT! Just when I needed to have my emissions checked.

Murphy strikes again!

I pulled up the DTCs in the DIC while I was driving and got a P-0442 code.

So,, I looked up the DTC and here is the definition:

DTC P0442

Description:
The EVAP small leak test applies vacuum to the evaporative emission (EVAP) system and monitors vacuum decay. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum decay. If the system detects a leak larger than a calibrated amount, DTC P0442 will set.

Conditions for Running the DTC
DTC P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1120, P1220, or P1221 are not set.
The ignition voltage is between 10-18 volts.
The barometric pressure is more than 75 kPa.
The fuel level is between 15-85 percent.
The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
The intake air temperature (IAT) is between 4-30°C (39-86°F).
The start up ECT and IAT are within 9°C (16°F) of each other.
The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).
Conditions for Setting the DTC
The EVAP system can achieve a vacuum, but a vacuum decay is detected during the diagnostic test.

Action Taken When the DTC Sets
The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
The control module will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
Conditions for Clearing the MIL/DTC
The control module will turn the malfunction indicator lamp (MIL) OFF during the first trip in which the diagnostic has been run and passed.
A last test failed (current DTC) clears when the control module turns OFF the MIL.
The history DTC will clear after the control module runs and passes 40 consecutive warm up cycles with no failure.
The DTC can be cleared by using a scan tool.
Diagnostic Aids
To help locate intermittent leaks, use the EVAP pressure/purge diagnostic station to pressurize the EVAP system. Move all EVAP components while testing with the J 41416 Ultrasonic Leak Detector.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step verifies that a failure condition is active.

This step verifies that repairs are complete and that no other condition is present.

Step
Action
Values
Yes
No

Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram

1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

2
Does the scan tool indicate DTC P0443, P0449, P0452, P0453, or P1441 are also set?
--
Go to Diagnostic Trouble Code (DTC) List
Go to Step 3

3
Inspect the EVAP system for the following conditions:
Loose, missing or damaged service port schrader valve
Loose, incorrect, missing or damaged fuel fill cap
A damaged EVAP canister purge valve
Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
Inspect the EVAP system for the following conditions:
Disconnected, improperly routed, kinked or damaged EVAP pipes and hoses
A damaged EVAP canister vent valve or EVAP canister
Did you find and correct the condition?
--
Go to Step 6
Go to Step 4

4
With a scan tool, capture and record the Failure Records data and clear the DTCs.
Perform the Service Bay Test. Refer to Service Bay Test .
Does the scan tool indicate that the service bay test passed?
--
Go to Diagnostic Aids
Go to Step 5

5

Important
Always zero the EVAP pressure and vacuum (in H2O) gauges on the before proceeding with diagnosis.


Install the J 41415 Fuel Tank Cap Adaptor.
Connect the J 41413 EVAP Pressure/Purge Diagnostic Station and the vehicle fuel fill cap to the J 41415 .
Turn ON the ignition, with the engine OFF.
With the scan tool, seal the EVAP system.
With the J 41413 , continuously attempt to pressurize the EVAP system.

Important
It may be necessary to partially lower the fuel tank to inspect components located in the upper portion of the tank.


With the J 41416 Ultrasonic Leak Detector, inspect for leaks in the following locations:
The EVAP system purge pipe. Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine .
The EVAP vapor pipe. Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine .
The EVAP vent hose. Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine .
The fuel fill pipe/hose and fuel fill cap. Refer to Filler Tube Replacement .
The EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
The EVAP canister vent valve. Refer to Evaporative Emission (EVAP) Canister Vent Valve Replacement .
The EVAP canister purge valve. Refer to Evaporative Emission (EVAP) Canister Purge Valve Replacement .
The fuel sender assembly and/or seal. Refer to Fuel Sender Assembly Replacement .
The (FTP) fuel tank pressure sensor seal. Refer to Fuel Tank Pressure Sensor Replacement .
The fill limiter vent valve, pressure relief valve, rollover valves, permanent EVAP pipes and/or fuel tank. Refer to Fuel Tank Replacement .
Did you find and correct the condition?
15 in H2O
Go to Step 6
Go to Diagnostic Aids

6
Perform the Service Bay Test. Refer to Service Bay Test .

Does the scan tool indicate that the service bay test passed?
--
Go to Step 7
Go to Step 2

7
With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK



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Document ID# 794699
2002 Chevrolet Corvette


The first thing that I checked is the vacuum line on the manifold because I had the manifold off. That was fine.

The next thing is the GAS CAP! First I checked it to see if it was tight. YEP!

Removed it and examined the O ring. Man O MAN!!!! The O ring had more cracks than I could have counted!!

For now I will apply a little black RTV on the O ring so I can get thru emissions. Then I will see if I can find an O ring... Its a BIG sucker. If not, I will hit up Gene Culley for a new one.

Just making a LESSONS LEARNED for anyone who may need the assistance in the future.

Bill Curlee

 

Keep us posted on your status, with the emission test and that gas cap. would be nice to hear that's all it was

 

You bet ya!! Pictures to follow!!!

bc

 

I am looking forward to your results and the pics too!

Here in California they actually pull the Gas Cap off and stick it in a sucking maching to test it - man if that was mine here I would fail unless I could snag a friends for the test - (which I would )

I am going to check mine just for good measure

Thanks,Matt

 

Hi guys,
A few months ago, I did the oil pressure sensor relocation modification. All seems good but I notice the running a little rough. In addition, the air conditioning system is acting funky. All symptoms to a broken vacuum cap tube at the back of the intake. So now that I home for the weekend, it’s time to troubleshoot. What I was going to do is inspect the cap tube and replace with a vacuum hose, but I found this while dis-assembling the intake. See the pics.
I have the service manual on DVD but it does not work properly. Therefore, does anyone have any drawings on the EVAP system?

http://s690.photobucket.com/albums/vv268/6-speeder/