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 fuel tank vapor temperature occurs. In a sealed system 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 (FTP) sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 millimeter (0.02 inches) 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:
P0442 EVAP System Small Leak Detected
CONDITIONS FOR RUNNING THE DTC
- DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0151, P0152, P0153, P0154, P0155, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0313, P0443, P0446, P0449, P0452, P0453, P0454, P0458, P0459, P0496, P0498, P0499, P0500, P0722, P0723, P1111, P1112, P1114, P1115, P1791, P1795, P2100, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, P2234 are not set.
- The diagnostic runs once with 10-hour minimum between tests after a fail.
- DTC P0455 must run and PASS.
- The start-up intake air temperature (IAT) is between 4-30°C (39-86°F).
- The start-up engine coolant temperature (ECT) is less than 30°C (86°F).
- The start-up IAT and ECT are within 8°C (15°F).
- The barometric pressure (BARO) is more than 74 kPa.
- The ambient air temperature is between 2-32°C (36-90°F).
- The engine run time minimum is 10 minutes.
- The odometer displays more than 16 kilometers (10 miles).
- The vehicle has traveled more than 5 kilometers (3 miles) this trip.
- The ECT is more than 70°C (158°F).
- The fuel level is between 15-85 percent.
- The ignition is OFF.
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) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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
- A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool PURGE/SEAL function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay. This type of leak may be detected.
- To help locate intermittent leaks, use the J 41413-200 Evaporative Emission 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 Intermittent Conditions. Intermittent Conditions
TEST
