P0442

Evaporative Emission Control System Circuit:

Circuit Description
The evaporative leak detection diagnostic strategy is based on applying vacuum to the Evaporative Vapor (EVAP) system and monitoring vacuum decay. The Powertrain Control Module (PCM) monitors vacuum level via the fuel tank vacuum sensor input. At an appropriate time, the EVAP purge solenoid and the EVAP vent solenoid are turned "ON," allowing engine vacuum to draw a small vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP purge solenoid is turned "OFF," sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a given time period, all other variables remaining constant. A small leak in the system will cause DTC P0442 to be set.

Conditions for Setting the DTC
- The BARO is greater than 70 kPa
- The intake air temperature is between 4°C and 30°C at engine start up
- The engine coolant temperature is between 4°C and 30°C at engine start up
- The Engine Coolant Temperature (ECT) sensor and Intake Air Temperature (IAT) sensor are within 4°C at engine start up
- Fuel tank level is between 15% and 85%
- The Throttle Position (TP) sensor is between 9 and 35%
- The EVAP solenoid is enabled
- The EVAP system is unable to achieve or maintain vacuum during the diagnostic test. The amount of decay will vary with the fuel level.
- One or more of the following DTCs are not set P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn "OFF" after three consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTCs can be cleared by using a scan tool.

Diagnostic Aids
Check for the following conditions:
- Missing or damaged 0-rings at the fuel vapor fittings and the EVAP purge line canister fittings.
- Cracked EVAP canister.
- Damaged source vacuum line, EVAP purge line, EVAP vent hose or fuel tank vapor line.
- Poor connection at PCM- Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness. Inspect the wiring harness to the EVAP vent solenoid, the EVAP purge solenoid, and the fuel tank pressure sensor for an intermittent open or intermittent short circuit.

NOTE: Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.

DTC P0442 - Evaporative Emission Control System - Small Leak Detected (1 Of 3):

DTC P0442 - Evaporative Emission Control System - Small Leak Detected (2 Of 3):

DTC P0442 - Evaporative Emission Control System - Small Leak Detected (3 Of 3):

Test Description
Numbers below refer to the step numbers on the Diagnostic Table.
1. The OBD System Check prompts the Technician to complete some basic checks and store the Freeze Frame Data and the Failure records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. This information on the scan tool can be referred to later.
2. If a vent solenoid or EVAP purge solenoid electrical fault is present, the purge system will not operate correctly. Repairing the electrical fault will very likely correct the condition that set DTC P0442.
6. Checks the fuel tank vacuum sensor at ambient pressure.
7. Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes.