P1441

Diagnostic Chart:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) tests the evaporative emission (EVAP) system for the following conditions:
^ Large and small leaks (P0440 and P0442)
^ Excess vacuum (P0446)
^ Purge flow during non-commanded conditions (P1441)
^ Fuel tank pressure sensor and fuel level sensor faults (P0452, P0453, P0462 and P0463)
^ EVAP purge and vent valve faults (P0443 and P0449)

The PCM monitors the amount of vacuum in the EVAP system by monitoring the fuel tank pressure sensor. For this Diagnostic Trouble Code (DTC) the PCM turns OFF the EVAP purge valve and turns ON the EVAP vent valve when the Conditions for Running the DTC have been met. This test indicates a leaking EVAP purge valve or flow during non-purge if the fuel tank pressure sensor indicates increasing fuel tank vacuum. This DTC will set after two consecutive failures of the above test.

CONDITIONS FOR RUNNING THE DTC
^ The following types of DTCs are not set:
^ Misfire
^ Fuel trim
^ Injector control circuit
^ AIR system
^ Exhaust Gas Recirculation (EGR) system
^ Vehicle Speed Sensor (VSS)
^ Heated Oxygen Sensor (HO2S)
^ Throttle Position (TP) sensor
^ Manifold Absolute Pressure (MAP) sensor
^ Mass Air Flow (MAF) sensor
^ Engine Coolant Temperature (ECT) sensor
^ Intake Air Temperature (IAT) sensor
^ The battery voltage is between 5-18 volts.
^ The barometric pressure is more than 75 kPa.
^ The fuel level is between 15-85 percent of full capacity for at least 10 seconds continuously. The time limit is required because fuel sloshing within the tank may cause the fuel level indication to vary outside the fuel level limits.
^ The ECT at start up was between 4°C-30°C (40°F-86°F).
^ The IAT at start up was between 4°C-30°C (40°F-86°F).
^ ECT not more than 8°C (14.4°F) above or 2°C (3.6°F) below IAT at start up.

CONDITIONS FOR SETTING THE DTC
An increasing vacuum in the EVAP system is monitored.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle 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 ignition cycle, 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 during which the diagnostic runs and passes.
^ A last test failed, or the current DTC, clears when the diagnostic runs and passes
^ A History DTC clears after forty consecutive warm-up cycles, if no other emission related diagnostic failures are reported.
^ Use a scan tool in order to clear the MIL diagnostic trouble code.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module (PCM) Description, Clearing Diagnostic Trouble Codes.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

IMPORTANT: An accurate indication of fuel level is required for the PCM to properly Pass or Fail this DTC. Always diagnose fuel level sensor DTCs before performing this DTCs diagnostic table. Always check for fuel level sensor DTCs stored as History.

Perform a physical inspection of the EVAP system. Check for the following conditions:
^ Incorrectly routed or defective EVAP system vacuum and vapour lines
^ A stuck open EVAP purge valve
^ A malfunctioning or damaged vapor canister

Check for charcoal release from the vapor canister. Refer to the EVAP System Cleaning procedure.

If the problem is intermittent, refer to intermittent Conditions. Intermittent Conditions




The vacuum and pressure in the EVAP system is measured in inches of Water (H2O). Most gauges measure vacuum in inches of Mercury (Hg) and pressure in pounds per square inch (psi). The table shows how the values compare.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. This DTC should only set if an increasing vacuum was monitored by the PCM while the EVAP vent and purge valves were both sealed.
Check for possible carbon contamination of the EVAP purge solenoid valve and the purge line.