The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, 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 solenoid valves.
Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
---|---|---|
ON | Open | Closed |
OFF | Closed | Open |
This diagnostic procedure supports the following DTC:
DTC P0455 EVAP System Large Leak Detected
• | DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0221, P0222, P0223, P0443, P0446, P0449, P0451, P0452, P0453, P0455, P0458, P0459, P0498, P0499, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176 are not set. |
• | The engine is running. |
• | The ignition voltage is between 10.5-17.3 volts. |
• | The barometric pressure (BARO) is more than 68 kPa. |
• | The fuel level is between 15-85 percent. |
• | The intake air temperature (IAT) is between 4-35°C (39-95°F). |
• | The start-up engine coolant temperature (ECT) and IAT are within 9°C (16°F) of each other. |
• | The vehicle speed is 0 km/h (0 mph). |
The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.
• | 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. |
• | 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. |
• | If DTC P0442, P0446, P0455 is set, EVAP special functions on the scan tool will not be allowed. Clear the DTCs before performing these tests. |
• | The ECM uses the FTP sensor to detect the pressure of fuel vapor in the fuel tank during all parts of the EVAP diagnostic system test. Ensure the FTP sensor is not skewed by verifying FTP sensor on the scan tool is between 2.35-2.85 volts with the ignition ON and the engine OFF. |
• | The following are possible causes of a large EVAP leak: |
- | The fuel cap is missing, incorrectly installed, or leaking. |
- | The EVAP canister vent solenoid valve is stuck open. |
- | The EVAP canister purge solenoid valve is stuck closed/blocked or a lack of manifold vacuum to solenoid. |
- | The EVAP line/hose connections are disconnected/leaking. |
- | The fuel sender O-ring is leaking. |
- | The FTP sensor seal is leaking. |
• | To help locate intermittent leaks, use the J 41413-200 (J 41413-100) Evaporative Emission System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the High Intensity White Light. |
• | To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the High Intensity White Light. |
• | Review the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition. |
• | For intermittent conditions, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Evaporative Emissions Hose Routing Diagram | ||||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||||
2 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 3 | ||||||||||
3 |
Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
Is the floating indicator below the red flag? | -- | Go to Step 6 | Go to Step 4 | ||||||||||
4 |
Important: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
Did you locate and repair a leak source? | -- | Go to Step 17 | Go to Step 5 | ||||||||||
5 |
Did you locate and repair a leak source? | -- | Go to Step 17 | Go to Step 6 | ||||||||||
6 |
Is the scan tool fuel tank pressure sensor parameter within the specified value of the J 41413-200 (J 41413-100) pressure/vacuum gage? | +1 to -1 in H2O | Go to Step 7 | Go to Step 13 | ||||||||||
7 |
Is the fuel tank pressure sensor parameter more than the second specified value? | 10 in H2O 5 in H2O | Go to Step 8 | Go to Step 13 | ||||||||||
8 |
Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Diagnostic Aids | Go to Step 9 | ||||||||||
9 | Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 14 | Go to Step 10 | ||||||||||
10 | Disconnect the EVAP purge pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 15 | Go to Step 11 | ||||||||||
11 | Disconnect the EVAP vapor pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 16 | Go to Step 12 | ||||||||||
12 | Repair the pinched or obstructed EVAP vapor pipe. Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||||
13 | Replace the fuel tank pressure (FTP) sensor. Refer to Fuel Tank Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||||
14 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||||
15 | Repair the restriction in the EVAP purge pipe. Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||||
16 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||||
17 |
Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
Is the floating indicator below the red flag? | 5 in H2O | Go to Step 18 | Go to Step 4 | ||||||||||
18 | Observe the fuel tank pressure sensor parameter with a scan tool. Is the scan tool fuel tank pressure parameter within the specified value of the J 41413-200 (J 41413-100) pressure/vacuum gage? | 1 in H2O | Go to Step 19 | Go to Step 6 | ||||||||||
19 |
Does the pressure decrease? | -- | Go to Step 20 | Go to Step 9 | ||||||||||
20 | 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 in Vehicle DTC Information | System OK |