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 canister 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 Valve | EVAP Canister Vent Valve |
---|---|---|
ON | Open | Closed |
OFF | Closed | Open |
• | DTC P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0221, P0222, P0223, P0443, P0449, P0451, P0452, P0453, P0458, P0459, P0498, P0499, P0500, P0560, P0562, P0563, P2122, P2123, P2127, P2128, P2138 are not set. |
• | The engine has been running for 17 minutes or the fuel trim is stable. |
• | The engine is idling. |
• | The engine is operating in Closed Loop. |
• | The battery voltage is between 10.5-18 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 2-35°C (39-95°F). |
• | The start-up ECT and IAT are within 9°C (16°F) of each other. |
• | The fuel tank pressure (FTP) is between -19 and +7.5 mm Hg (-10 and +4 in H2O). |
• | The vehicle speed sensor (VSS) 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. |
• | To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner. |
• | A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system. |
• | To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT . |
• | 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. |
The numbers below refer to the step numbers on the diagnostic table.
This step verifies that a failure condition is active.
Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
This step verifies proper operation of the FTP sensor.
A normal operating FTP sensor should increase above 5 inches of H2O and Stop between 6 inches of H2O and 7 inches of H2O.
This step tests the EVAP canister purge solenoid valve vacuum source between the EVAP canister purge solenoid valve and the Intake manifold for restrictions or blockages.
Step | Action | Values | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Evaporative Emissions Hose Routing Diagram | ||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||
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 Diagnostic Aids | Go to Step 3 | |||||||||||
3 |
Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 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. The system flow will be less with higher temperatures.
Did you locate and repair a leak source? | -- | Go to Step 19 | Go to Step 5 | |||||||||||
5 |
Did you locate and repair a leak source? | -- | Go to Step 19 | Go to Step 6 | ||||||||||
Is the scan tool Fuel Tank Pressure parameter within the specified value of the J 41413-200 pressure/vacuum gage? | 1 in H2O | Go to Step 7 | Go to Step 15 | |||||||||||
Is the Fuel Tank Pressure parameter more than the specified value? | 5 in H2O | Go to Step 8 | Go to Step 15 | |||||||||||
8 |
Is the Fuel Tank Pressure parameter less than the specified value? | 1 in H2O | Go to Diagnostic Aids | Go to Step 9 | ||||||||||
Disconnect the EVAP purge vacuum source from the EVAP canister purge solenoid valve. Is the Fuel Tank Pressure parameter less than the specified value? | 1 in H2O | Go to Step 13 | Go to Step 10 | |||||||||||
10 | Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve. Is the Fuel Tank Pressure parameter less than the specified value? | 1 in H2O | Go to Step 16 | Go to Step 11 | ||||||||||
11 | Disconnect the EVAP purge pipe at the EVAP canister. Is the Fuel Tank Pressure parameter less than the specified value? | 1 in H2O | Go to Step 17 | Go to Step 12 | ||||||||||
12 | Disconnect the EVAP vapor pipe at the EVAP canister. Is the Fuel Tank Pressure parameter less than the specified value? | 1 in H2O | Go to Step 18 | Go to Step 14 | ||||||||||
13 | Repair the pinched or obstructed EVAP purge solenoid vacuum source. Did you complete the repair? | -- | Go to Step 19 | -- | ||||||||||
14 | Repair the pinched or obstructed EVAP vapor pipe. Did you complete the repair? | -- | Go to Step 19 | -- | ||||||||||
15 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||
16 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||
17 | Repair the restriction in the EVAP purge pipe. Did you complete the repair? | -- | Go to Step 19 | -- | ||||||||||
18 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||
19 |
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 20 | Go to Step 5 | ||||||||||
20 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK |