P1441

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The PCM monitors the amount of vacuum/pressure in the EVAP system by monitoring the fuel tank pressure 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 greater than a predetermined value within a predetermined time.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0420, P0430, P0500, P0502, P0503, P1111, P1112, P1114, P1115, and HO2S DTCs are not set.
- The ignition voltage is between 10.0 volts and 17.0 volts.
- The barometric pressure is greater than 75 kPa.
- The fuel level is between 15% and 85% of full capacity.
- The engine coolant temperature is between 4°C (39°F) and 30°C (86°F).
- The intake air temperature is between 4°C (39°F) and 30°C (86°F).
- The start up engine coolant and intake air temperatures are within 9°C (16°F) of each other.
- The EVAP Purge Solenoid duty cycle is 0%. The angle is between 0% and 99.6%.

CONDITIONS FOR SETTING THE DTC
The EVAP system develops a vacuum greater than a predetermined value when purge is not commanded.

ACTION TAKEN WHEN THE DTC SETS
The PCM illuminates the Malfunction Indicator Lamp on the second consecutive drive trip that the diagnostic runs and fails.

The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
- A last test failed (current DTC) clears when the diagnostic runs and does not fail.
- A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
- The PCM battery voltage is interrupted.
- Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
Before replacing any components, visually/physically check for the following:
- Mis-routed 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. Testing and Inspection

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
5. Since the vacuum switch only requires a vacuum of only a few inches of water to operate (a very small unit of vacuum), a properly operating switch will transition even with the canister end of the hose disconnected and un-plugged.