hi problem solvers, my 2002 camero convertible 3.8 l is throwing p0446 code . i replaced the gas cap with no improvement. code is a vent solenoid problem. the problem is the vent solenoid is located on top of the gas tank. i plan to access the solenoid with a cut out flap in the deck,a process i've used to replace the fuel sender.before a start cutting does anyone have a flow sheet for diagnosing this code ? thanks for any help.

 

Hope it helps...

Document ID# 794655
2002 Chevrolet Camaro
DTC P0446

System Description

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid Open and the EVAP canister vent solenoid Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid Closed and the EVAP canister vent solenoid Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent valves.

Control Module Command

EVAP Canister Purge Solenoid

EVAP Canister Vent Solenoid

ON

Open

Closed

OFF

Closed

Open

Conditions for Running the DTC

DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1120, P1220, or P1221 are not set.
The ignition voltage is between 10-18 volts.
The barometric pressure (BARO) 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).
The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).
Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids

An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP vent valve inlet or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.

Test Description

The number below refers to the step number on the diagnostic table.

This test determines if the fuel tank pressure (FTP) sensor is functioning.

Step

Action

Value(s)

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

Did DTC P0443, P0449, P0452, or P0453 set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

Inspect the evaporative emission (EVAP) system for the following conditions:

A damaged EVAP vent valve
A pinched EVAP fresh air vent hose
Did you find and correct the condition?

--

Go to Step 14

Go to Step 4

4

Disconnect the purge line from the EVAP purge valve.
Turn ON the ignition, with the engine OFF.
With a scan tool, observe the fuel tank pressure (FTP) parameter.
Does the scan tool indicate fuel tank pressure near the specified value?

0 in H2O

Go to Step 5

Go to Step 8

5


Important

Always zero the EVAP pressure and vacuum (in H2O) gauges on the J 41413 EVAP Pressure/Purge Diagnostic Station before proceeding with diagnosis.

Turn OFF the ignition.
Reconnect all previously disconnected hardware.
Install the J 41416 Fuel Tank Cap Adaptor.
Connect the J 41413 and the vehicle fuel fill cap to the J 41416 .
Turn ON the ignition, with the engine OFF.
Command the EVAP canister vent valve ON with a scan tool.

Important

Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

With the J 41413 , pressurize the EVAP system to the first specified value.
Rotate the EVAP pressure/purge diagnostic station rotary switch to the OFF/HOLD position.
Command the EVAP canister vent valve OFF with a scan tool.
Does the scan tool indicate fuel tank pressure FTP near the second specified value?

5 in H2O

0 in H2O

Go to Diagnostic Aids

Go to Step 6

6

Disconnect the EVAP canister vent hose from the EVAP canister vent valve.

Does the scan tool indicate that the fuel tank pressure is within the specified range?

-0.5 to +0.5 in H2O

Go to Step 10

Go to Step 7

7

Disconnect the EVAP vent hose from the EVAP canister.

Does the scan tool indicate FTP near the second specified value?

0 in H2O

Go to Step 13

Go to Step 11

8

With a scan tool, observe the FTP sensor voltage.

Is the FTP sensor voltage more than the specified value?

4.3 V

Go to DTC P0453

Go to Step 9

9

Test for poor connections at the harness connector of the FTP sensor. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

10

Replace the EVAP canister vent valve. Refer to Evaporative Emission (EVAP) Canister Vent Valve Replacement .

Did you complete the replacement?

--

Go to Step 14

--

11

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

Did you complete the replacement?

--

Go to Step 14

--

12

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

Did you complete the replacement?

--

Go to Step 14

--

13

Repair for a blockage in the EVAP vent hose.

Did you complete the repair?

--

Go to Step 14

--

14

Turn ON the ignition, with the engine OFF.
Command the EVAP canister vent valve ON with a scan tool.

Important

Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

Pressurize the EVAP system to the specified value with the J 41413 .
Place the control **** on the J 41413 to the OFF/HOLD position.
Monitor the J 41413 pressure gage.
Command the EVAP canister vent valve OFF.
Does the EVAP system pressure decrease?

--

Go to Step 15

Go to Step 3

15

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

Document ID# 794655
2002 Chevrolet Camaro

 

THANKS FOR THE QUICK reply will check this out before cutting the deck

 

update ,cut deck to expose the vent valve and replaced it.code still present. checked voltage to vent valve 14 v.but the vent didnt close . when i grounded the valve it closed. so i guess the ground wire is the problem. does anyone have a schematic for a 2002 3.8 camaro convertible?

 

should be in the repair manual look here My Files

 

thanks craby for the schematic i found the ground wire for the vent solenoid c2 45. on the pcm. is there a pictorial diagram for the pcm plug.? the camero has two plugs to the pcm and i dont know how to locate c2 45 to check the ground. thanks again for the great help, the solution is near .

 

this help
Connector Part Information

 

hi craby, traced the ground to the pcm it was ok.the problem is with the pcm, its not switching the ground on.this is our new hi tech systems malfouctions,spend $$$ to replace a pcm just so it can do a test which doesnt affect the cars function. thanks for all the help with dxing this problem

 

one more thought, i can manually activate the vent solenoid. does anyone know how many minutes the pcm keeps this valve closed?maybe i can still defeat this malfunction to get thru inspection