Circuit Description
The powertrain control module (PCM) monitors the amount of vacuum pressure in the evaporative emissions (EVAP) system by monitoring the fuel tank pressure (FTP) sensor signal. The PCM seals the EVAP system by commanding the EVAP purge solenoid OFF and the EVAP vent valve ON. The PCM monitors the fuel tank pressure sensor in order to determine if the EVAP purge solenoid is leaking vacuum to the EVAP system. This DTC sets if the vacuum in the EVAP system is more than a predetermined value within a predetermined time.
Conditions for Running the DTC
| • | DTCs P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0131-P0161, P0420, P0430, P0500, P0502, P0503, P0562, P0563, P1111, P1112, P1114, or P1115, are not set. |
| • | No active manifold absolute pressure (MAP) DTCs |
| • | No active intake air temperature (IAT) DTCs |
| • | No active throttle position (TP) DTCs |
| • | No active heated oxygen sensor (HO2S) DTCs |
| • | No active vehicle speed sensor (VSS) DTCs |
| • | No active system voltage DTCs |
| • | 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 of full capacity. |
| • | The engine coolant temperature (ECT) is between 4-30°C (39-86°F). |
| • | The intake air temperature is between 4-30°C (39-86°F). |
| • | The start up engine coolant and intake air temperatures (IAT) are within 8°C (14°F) of each other. |
| • | The throttle position (TP) angle is between 0-99.6 percent. |
Conditions for Setting the DTC
The EVAP system develops a vacuum more than a predetermined value when purge is not commanded.
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
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
Before replacing any components, visually and physically check for the following:
| • | Misrouted harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
| • | Kinked or damaged vacuum hoses |
| • | Physically damaged system components |
| • | Inspect components and vacuum lines for traces of carbon or other contaminants. The presence of foreign material may be causing a restriction in the system or preventing the solenoid valve from closing properly. Either condition may cause a DTC to set. |
For an intermittent condition, refer to Symptoms - Engine Controls .
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Emission Hose Routing Diagram and Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Are DTCs P0443, P0449, P0452 or P0453 also set? | -- | Go to Step 3 | |
3 |
Does the scan tool indicate fuel tank pressure within the specified range? | -0.5 to +0.5 in H2O | Go to Step 5 | Go to Step 4 |
4 |
Does the scan tool indicate fuel tank pressure within the specified range? | -0.5 to +0.5 in H2O | Go to Step 6 | Go to DTC P0453 |
5 |
Does the EVAP diagnostic station indicate an increase in vacuum? | -- | Go to Step 7 | Go to Diagnostic Aids |
6 | Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- |
7 | Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- |
Does the scan tool indicate that the Service Bay Test has passed? | -- | Go to Step 9 | Go to Step 3 | |
9 | With a scan tool, select the Review Info option Does the scan tool indicate any DTCs that have not been diagnosed? | -- | System OK | |
