System Description
This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined 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 solenoid valves.
Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
ON | Open | Closed |
OFF | Closed | Open |
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0221, P0222, P0223, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0458, P0459, P0498, P0499 are not set. |
| • | The engine is operating in Closed Loop. |
| • | The engine is idling. |
| • | The engine has been running for 17 minutes or the fuel trim is stable. |
| • | The battery voltage is between 10.5-18 volts. |
| • | The start-up idle air temperature (IAT) is between 2-35°C (39-95°F). |
| • | The start-up engine coolant temperature (ECT) and IAT are within 9°C (16°F) of each other. |
| • | The fuel tank level is between 15-85 percent. |
| • | The fuel tank pressure (FTP) is between -19 and +7.5 mm Hg (-10 and +4 in H2O). |
| • | The barometric pressure (BARO) is more than 68 kPa (10.8 psi). |
| • | The vehicle speed sensor (VSS) is 0 km/h (0 mph). |
Conditions for Setting the DTC
The control module detects vacuum during a non-purge condition.
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 an improperly installed or damaged EVAP canister purge solenoid valve or a temporary blockage in the EVAP canister purge solenoid valve. Inspect for blockage in the EVAP system.
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 | |
2 | Is DTC P0443, P0449, P0451, P0452, P0453, P0458 P0459, P0498, or P0499 also set? | -- | Go to Step 3 | |
3 |
Is the fuel tank vacuum press. parameter within the specified range? | -0.5 to +0.5 in H2O | Go to Step 4 | Go to DTC P0451 |
4 |
Does the gage indicate an increase in vacuum? | 1,200-1,500 RPM | Go to Step 5 | Go to Diagnostic Aids |
5 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 6 | -- |
6 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Steps 7 |
7 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
