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Home >> Isuzu Truck >> 2000 >> Hombre XS Regular Cab 2WD L4-2.2L CPC >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0442

P0442

DTC P0442 Evaporative Emission (EVAP) System Small Leak Detected




Circuit Description
The evaporative system includes the following components.
- The fuel tank
- The EVAP vent solenoid
- The fuel tank pressure sensor
- The fuel pipes and hoses
- The fuel vapor lines
- The fuel cap
- The EVAP canister
- The purge lines
- The EVAP canister purge solenoid valve
- The EVAP service port

The evaporative emission system is checked by applying vacuum to the EVAP system and by monitoring for a vacuum decay. The PCM monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge solenoid valve and the EVAP vent solenoid are turned ON, allowing the engine to draw a small vacuum on the entire evaporative emission system. Once the desired vacuum level has been achieved, the EVAP canister purge solenoid valve turns OFF, sealing the system. A small leak in the system will cause DTC P0442 to set.

Conditions for Running the DTC
- No active MAP DTC's
- No active IAT DTC's
- No active ECT DTC's
- No active TP DTC's
- No active Oxygen Sensor DTC's
- No active Fuel Tank Pressure DTC's
- No active VSS DTC's
- No active PCM Memory DTC's
- The BARO is more than 75 kPa.
- The intake air temperature is between 5° C and 29° C (41° F and 84° F) at engine start up.
- The engine coolant temperature is between 5° C and 29° C (41° F and 84° F) at engine start up.
- The Intake Air Temperature is not more than 1° C (2° F) more than the Engine Coolant Temperature at start up.
- The Engine Coolant Temperature is not more than 7° C (12° F) more than the Intake Air Temperature at start up.
- The fuel tank level is between 15 percent and 85 percent
- The TP sensor is between 7 percent and 35 percent.

Conditions for Setting the DTC
The EVAP system is unable to detect vacuum during the diagnostic test.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.
- A history DTC stores.

Conditions for Clearing the MIL/DTC
- The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs a pass.
- A history DTC will clear after 40 consecutive warm up cycles without a malfunction.
- A scan tool can clear the DTCs.

Diagnostic Aids
- A loose, missing, or damaged fuel cap.
- Missing or damaged O-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.

Check for charcoal particles. Refer to EVAP System Cleaning before starting repairs.

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

Steps 1 - 2:




Steps 3 - 4:




Step 5:




Steps 6 - 7:




Steps 8 - 10:




Step 11:




Steps 12 - 14:




Test Description
The numbers below refers to the step numbers on the Diagnostic Table.
1. The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data for later reference.
3. If a vent solenoid or an EVAP canister purge valve electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction will very likely correct the condition that set DTC P0442.
4. This step checks the fuel tank pressure sensor at the ambient pressure.
5. This step verifies that the fuel tank pressure sensor accurately reacts to the EVAP system pressure changes.
12. This step insures proper system integrity.
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