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Emissions routing diagrams needed


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I am currently trying to chase down a P0442 code (wassn't the gas cap :sigh: ), I have a friend that has a smoke tester that I can use this weekend, but it would really help to have diagrams of where most everything runs. I know there used to be some diagrams in the wiki, but I can't find a link to it, is the wiki gone? Could be I am just blind.

 

So please post up if you have any diagrams that might relate, Thanks!

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Emission Hose Routing Diagram

 

 

 



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(1) Manifold Absolute Pressure (MAP) Sensor (2) EVAP Canister Purge Hose (3) EVAP Service Port (4) Positive Crankcase Ventilation (PCV) Valve (5) Throttle Body (6) EVAP Purge Solenoid (7) AIR Module

 

 

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DTC P0442 Evaporative Emission (EVAP) System Small Leak Detected

 

Table 1: DTC P0440 and P0442

 

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Circuit Description

 

The PCM tests the EVAP system for the following conditions:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The PCM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The PCM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the Conditions for Running the DTC are met in order to apply an engine vacuum to the EVAP system. The PCM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. The EVAP system should HOLD the vacuum in the sealed system. The PCM sets this DTC in order to indicate a small leak if the EVAP system fails to hold a predetermined level of vacuum for a predetermined length of time. This DTC sets after failing the above test twice.

Conditions for Running the DTC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Conditions for Setting the DTC

 

The vacuum in the EVAP system decays (leaks) at too fast a rate.Important: This DTC does NOT report a first failed test. A first fail of this DTC will have a scan tool status as Not Run. Use the scan tool data display parameter of EVAP Test Result to determine if this DTC has failed or passed for this ignition cycle.

Action Taken When the DTC Sets

 

 

 

 

 

 

Conditions for Clearing the MIL/DTC

 

 

 

 

 

 

 

 

 

 

 

 

Diagnostic Aids

Important:

 

 

 

 

 

 

 

 

 

 

 

 

 

Conditions for Running the Service Bay Test

 

 

 

 

 

 

 

 

 

 

Perform a physical inspection of the EVAP system. Inspect for the following conditions:

 

 

 

 

 

 

 

 

 

 

 

 

The vacuum and pressure in the EVAP system is measured in inches of H2O (water). Most gauges measure vacuum in inches of Hg (mercury) and pressure in psi (pounds per square inch). The following table illustrates how the values compare:

 

in. H2O

 

 

 

in. Hg.

 

 

 

psi

 

 

 

1 in. H2O

 

 

0.07 in. Hg

 

 

0.0361 psi.

 

 

5 in. H2O

 

 

0.36 in. Hg

 

 

0.180 psi.

 

 

10 in. H2O

 

 

0.73 in. Hg

 

 

0.361 psi.

 

 

15 in. H2O

 

 

1.10 in. Hg

 

 

0.541 psi.

 

Test Description

 

The numbers below refer to the step numbers on the Diagnostic Table.

3 It may be necessary to partially lower the fuel tank to inspect the upper portion of the tank and the EVAP line connections.

 

 

4 An intermittent leak or restriction is indicated if the vehicle passes the Service Bay Test. A fuel tank cap that is loose or off causes this DTC to set.

If the Service Bay Test can not be run, proceed to Step 5. If a fault is not currently present the diagnostic table steps will return you to Step 3.

 

 

12 Refer to the information supplied with the EVAP pressure/purge diagnostic cart on proper setup and adjustment procedures.

This step tests for a leak at the top of the fuel tank, at the fuel filler hose, and the fuel cap. Place the ultrasonic leak detector in these areas.

 

 

13 With pressure applied it may be necessary to disconnect the EVAP lines at the components to verify that a line or component is not restricted. A restriction would prevent a vacuum (or the Step 10 test pressure) from forming in the fuel tank.

 

 

19 A Fuel Tank Pressure sensor that does not correctly respond to pressure (or vacuum) causes this DTC to set.

The Fuel Tank Pressure sensor range is from 7.5 in. H2O of pressure to −17.5 in. H2O of pressure (vacuum).

In order to test the Fuel Tank Pressure sensor for vacuum response, command the EVAP Purge Solenoid Valve ON with the engine running and quickly SEAL the system. Leaving the EVAP Purge Solenoid Valve ON for a longer period of time allows a greater level of vacuum to develop.

 

 

Step

 

 

 

Action

 

 

 

Value(s)

 

 

 

Yes

 

 

 

No

 

 

 

1

 

 

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

 

 

 

 

Go to Step 2

 

 

Go to Powertrain On Board Diagnostic (OBD) System Check

 

 

2

 

 

Are any other EVAP system DTC's stored in history?

 

 

 

 

Go to applicable DTC

 

 

Go to Step 3

 

 

3

 

 

Inspect the EVAP system for the following conditions:

 

 

 

• A loose, incorrect, defective or missing fuel tank cap.

 

 

 

• Disconnected, improperly routed, kinked or damaged EVAP system purge lines.

 

 

 

• A damaged EVAP system component.

 

 

 

• A loose, missing, or damaged service port dust cap and/or schrader valve. Refer to the test description for additional information.

 

 

Repair the EVAP system if needed.

 

Did you find and repair the condition?

 

 

 

 

Go to Step 21

 

 

Go to Step 4

 

 

4

 

 

Important: Ensure that The Conditions for Running the Service Bay test are met before proceeding with this diagnostic. Refer to Diagnostic Aids.

Perform the EVAP system Service Bay Test using a scan tool.

 

Does the EVAP diagnostic pass the Service Bay Test?

 

 

 

 

Go to Diagnostic Aids

 

 

Go to Step 5

 

 

5

 

 

Important: The DTCs must be cleared from the PCM in order to use the output control function on the scan tool.

 

 

 

 

 

 

 

 

 

 

 

Can the value specified be obtained and held?

 

 

10 in Hg

 

 

Go to Step 6

 

 

Go to Step 15

 

 

6

 

 

Important: If an audible solenoid click cannot be heard and DTC P0443 is not set, inspect the EVAP canister purge solenoid circuits for high resistance.

 

 

 

 

 

 

 

Is the vacuum measured on the gauge the same or more than the specified value?

 

 

12 in Hg

 

 

Go to Step 8

 

 

Go to Step 7

 

 

7

 

 

 

 

 

 

 

 

 

 

 

Is the vacuum measured on the gauge the same or more than the specified value?

 

 

12 in Hg

 

 

Go to Step 15

 

 

Go to Step 14

 

 

8

 

 

 

 

 

 

 

 

 

 

 

Can the specified value of vacuum be obtained and held?

 

 

5 in Hg

 

 

Go to Step 9

 

 

Go to Step 18

 

 

9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Can the specified value of vacuum be obtained and held?

 

 

5 in Hg

 

 

Go to Step 12

 

 

Go to Step 10

 

 

10

 

 

 

 

 

 

 

 

 

 

 

Can the specified value of vacuum be obtained and held?

 

 

5 in. Hg.

 

 

Go to Step 16

 

 

Go to Step 11

 

 

11

 

 

 

 

 

 

 

Did you find and correct the condition?

 

 

 

 

Go to Step 21

 

 

Go to Step 17

 

 

12

 

 

Important: The following steps require the EVAP Pressure/Purge Diagnostic Station J 41413 and the Ultrasonic Leak Detector . Always zero the EVAP Pressure and Vacuum (in. H2O) gauges on the EVAP Pressure/Purge Diagnostic Station before proceeding with diagnosis.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Did you find and repair the condition?

 

 

 

 

Go to Step 21

 

 

Go to Step 13

 

 

13

 

 

 

 

 

 

 

Did you find and correct the condition?

 

 

 

 

Go to Step 21

 

 

Go to Step 19

 

 

14

 

 

Repair the vacuum source to the EVAP Purge Solenoid Valve.

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

15

 

 

Important: Inspect the EVAP Purge Solenoid Valve and the purge line for carbon contamination. Refer to Diagnostic Aids .

Replace the EVAP Purge Solenoid Valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

16

 

 

Replace the EVAP Vent Valve. Refer to Evaporative Emission Vent Valve Replacement .

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

17

 

 

Replace the EVAP Vapor Canister. Refer to Evaporative Emission Canister Replacement .

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

18

 

 

Repair the EVAP line from the EVAP Purge solenoid valve to the EVAP canister as necessary.

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

<a href="http://gsi.xw.gm.com/newsi/showDoc.do?laborOpCode=&docSyskey=308358&cellId=30183&pubObjSyskey=4763503&from=sm&pubCellSyskey=1446413#td19">19

 

 

 

 

1. With the EVAP system pressurized, compare the EVAP pressure/purge diagnostic station pressure gauge (in. H20) reading to the Fuel Tank Pressure sensor reading on the scan tool.

 

 

 

2. Compare the readings with the system depressurized. Refer to the Test Description .

 

 

Does the Fuel Tank Pressure sensor indicate the actual amount of pressure in the EVAP system?

 

 

 

 

Go to Step 3

 

 

Go to Step 20

 

 

20

 

 

Replace the Fuel Tank Pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement .

 

Is the action complete?

 

 

 

 

Go to Step 21

 

 

 

 

21

 

 

 

 

1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.

 

 

 

2. Idle the engine at the normal operating temperature.

 

 

 

3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.

 

 

 

4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

 

 

Does the scan tool indicate that this test ran and passed?

 

 

 

 

Go to Step 22

 

 

Go to Step 2

 

 

22

 

 

Select the Capture Info option and the Review Info option using the scan tool.

 

Does the scan tool display any DTCs that you have not diagnosed?

 

 

 

 

Go to Applicable DTC

 

 

System OK

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  • 2 years later...

So, my code went away and I passed emissions two years ago. The code reappeared as I was driving away from the test center and I have been ignoring it for two years. So today we pulled out the smoke machine and hooked her up. What we found was a rather large hole in the vapor canister, it was rubbed into it by a handle on the front of the fuel tank and it makes sense that the code would come and go - probably somewhat based on the amount of fuel in the tank. I put a new canister on order and we put some JB weld on the old one in the mean time. Just wanted to share my findings. c84977b00de9710c525ef065a3d4825a.jpg

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