P0442

DTC P0442

SYSTEM DESCRIPTION
This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met.

Heat from the exhaust system is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, a change in the fuel tank vapor temperature occurs. With the EVAP System sealed, this results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 mm (0.020 in) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.

If the control module detects a pressure change less than a calibrated amount, DTC P0442 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0442 Evaporative Emission System Small Leak Detected

CONDITIONS FOR RUNNING THE DTC
- Before the powertrain control module (PCM) can report DTC P0442 failed, DTCs P0446, P0455, and P0496 must run and pass.
- DTCs P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0443, P0446, P0449, P0452, P0453, P0463, P0503, P1106, P1107, P1111, P1112, P1114, P1115, P1516, P2101, P2108, P2129, P2120, P2125, P2138, P2610 are not set.
- The diagnostic runs once with a 10-hour minimum between tests after a fail.
- The ignition voltage is between 10-18 volts.
- The intake air temperature (IAT) is between 4-30°C (39-86°F).
- The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
- The start up IAT and ECT are within 9°C (16°F).
- The barometric pressure (BARO) is more than 75 kPa.
- The vehicle has been driven more than 8.4 kilometers (5.2 miles) this trip.
- The fuel level is between 15-85 percent.
- DTC P0442 runs once per cold start when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The control module detects a pressure change that is less than a calibrated amount.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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
- To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
- To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT.
- For intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

TEST DESCRIPTION

Step 1 - Step 3:

Step 4 - Step 7:

The numbers below refer to the step numbers on the diagnostic table.
3. Introducing smoke in 15-second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
5. This step verifies that repairs are complete.