Diagnostic Aids
- The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill condition.
- An EVAP canister, vent hose, or vent solenoid valve that has restricted flow may cause this DTC to set. Using a purge solenoid command with a scan tool will allow vacuum to be applied to the system instead of pressure. With the engine running, the EVAP canister vent solenoid valve open and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 5 inches H2O.
- An EVAP canister filter that is restricted can cause this DTC to set. Refer to Evaporative Emission (EVAP) Canister Filter Replacement and Evaporative Emission (EVAP) System Cleaning .
- Disconnecting one component at a time while the EVAP system is under flow will help to pinpoint a restriction in the system.
- Reviewing the Failure 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.
- For intermittent conditions, refer to Intermittent Conditions .
DTC P0446
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
and Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views |
||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Inspect the evaporative emission (EVAP) system for the following conditions:
Did you find and correct the condition? |
- | Go to Step 21 | Go to Step 3 |
| 3 |
|
- | Go to Step 5 | Go to Step 4 |
| 4 |
|
- | Go to Step 5 | Go to Step 12 |
| 5 |
|
-1 to +1 in H2O | Go to Step 6 | Go to Step 14 |
| 6 |
IMPORTANT:
DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
IMPORTANT:
Refer to the J 41413-200
Evaporative Emissions System Tester (EEST) operation manual for detailed instructions. See Special Tools
.
|
10 in H2O 5 in H2O |
Go to Step 7 | Go to Step 13 |
| 7 |
|
1 in H2O | Go to Step 8 | Go to Step 14 |
| 8 | Did the Fuel Tank Pressure Sensor parameter on a scan tool display more than the specified value? | 3.2 V | Go to Step 9 | Go to Step 14 |
| 9 |
IMPORTANT:
DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
IMPORTANT:
Refer to the J 41413-200
operation manual for detailed instructions. See Special Tools
.
|
5 in H2O -1 to +1 in H2O |
Go to Step 10 | Go to Step 17 |
| 10 |
|
3 in H2O | Go to Step 11 | Go to Step 17 |
| 11 |
|
5 in H2O | Go to Step 17 | Go to Diagnostic Aids |
| 12 |
|
- | Go to Step 13 | Go to Step 18 |
| 13 | Test the EVAP canister vent solenoid control circuit for a short to ground. Refer to Testing for Short to Ground
and Wiring Repairs
. Did you find and correct the condition? |
- | Go to Step 21 | Go to Step 16 |
| 14 | Test for an intermittent and for a poor connection at the fuel tank pressure (FTP) sensor. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
- | Go to Step 21 | Go to Step 15 |
| 15 | Test the low reference circuit of the FTP sensor for an open or high resistance. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
- | Go to Step 21 | Go to Step 19 |
| 16 | Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
- | Go to Step 21 | Go to Step 20 |
| 17 | Inspect the EVAP vent system for a restriction. Did you find and correct the condition? |
- | Go to Step 21 | Go to Diagnostic Aids |
| 18 | Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement
. Did you complete the replacement? |
- | Go to Step 21 | - |
| 19 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement
. Did you complete the replacement? |
- | Go to Step 21 | - |
| 20 | Replace the powertrain control module (PCM). Refer to Control Module References
for replacement, setup, and programming. Did you complete the replacement? |
- | Go to Step 21 | - |
| 21 |
|
- | Go to Step 2 | Go to Step 22 |
| 22 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? |
- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |