For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0442 : Evaporative Emission (EVAP) System Small Leak Detected

### Circuit Description

The engine off natural vacuum (EONV) test is the small leak detection diagnostic for the evaporative emission system. 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 the fuel tank while the vehicle is operating. When the vehicle is turned OFF and the EVAP system is sealed a change in the fuel tank vapor temperature occurs which results in a corresponding pressure change in the fuel tank vapor space. This change is monitored by the ECM using the fuel tank pressure sensor input. With a leak in the system, the amount of pressure change will be less than that of a sealed system.

### Conditions for Running the DTC

• | DTCs P0101, P0102, P0103, P0112, P0113, P0114, P0116, P0117, P0118, P0443, P0446, P0449, P0452, P0453, P0455, P0461, P0462, P0463, P0496, P0502, P0506, P0507, and P2610, are not set.

• | The fuel level is between 10-90 percent.

• | The engine run time before engine shut-off was greater than 10 minutes.

• | The drive distance before engine shut-off was greater than 5 kilometers (3.1 miles).

• | The engine coolant temperature (ECT) is greater than 70°C (158°F).

• | The barometric pressure (BARO) is greater than 70 kPa.

• | The ambient air temperature at the end of the drive cycle is between 0-34°C (32-93°F).

• | The ignition voltage is between 11-18 volts.

• | No fuel filling during the EONV test period.

• | The start-up ECT and start-up IAT are between 4-30°C (39-86°F).

• | The ignition is OFF.

• | The DTC runs once per drive cycle during the hot soak period after the ignition is turned OFF and may require up to 40 minutes to complete. The controller will not make more than 2 test attempts per day. The time since the last completed EONV test must be at least 17 hours or 10 hours if the system is failing.

### Conditions for Setting the DTC

The control module detects a leak in the EVAP system that is greater than a calibrated amount.

### Action Taken When the DTC Sets

DTC P0442 is a Type A DTC.

### Conditions for Clearing the DTC

DTC P0442 is a Type A DTC.

### Diagnostic Aids

• | A condition may exist where a leak in the EVAP system exists only under a vacuum condition. Test for this condition by using a scan tool Purge/Seal function to create a vacuum, then observe the FTP parameter for a vacuum decay.

• | 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 . Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.

• | To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT High Intensity White Light.

• | The EVAP system can also be tested from the front of the vehicle using the CH-48096 .

• | Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

### Reference Information

#### Schematic Reference

Evaporative Emissions Hose Routing Diagram

#### Description and Operation

Evaporative Emission Control System Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

• | J 41413-SPT High Intensity White Light

• | J 41413-200 Evaporative Emissions System Tester (EEST)

• | GE-41415-50 Fuel Tank Cap Adapter

### Circuit/System Verification

1. Verify the following conditions do not exist in the EVAP system:

• | Loose, incorrect, missing, or damaged fuel fill cap

• | A damaged EVAP purge solenoid

• | Disconnected, incorrectly routed, kinked, or damaged EVAP pipes and hoses

• | A damaged EVAP vent valve or EVAP canister

⇒ | If you find any of the above conditions, repair as necessary.

Note: Refer to the J 41413-200 operation manual for detailed instructions.

2. Remove the fuel fill cap. Connect the GE-41415-50 to the fuel tank filler neck. Connect the J 41413-200 to the GE-41415-50 .
3. Turn the nitrogen/smoke valve on the control panel to nitrogen.
4. Calibrate the J 41413-200 Flow Meter to the correct leak orifice for the vehicle.

Note:

• | Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

• | Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. The system flow will be less with higher temperatures.

5. Use the remote switch to activate the J 41413-200 and compare the flow meter's stable floating indicator position to the red flag. The floating indicator should be below the red flag.
6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, turn the nitrogen/smoke valve on the control panel to SMOKE.
2. Ignition ON, command the EVAP vent solenoid ON with a scan tool.

Note:

• | Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

• | Introduce smoke at 15 second intervals while testing the system.

• | The fuel sender may need to be accessed to inspect some of the EVAP system components.

3. Use the remote switch to introduce smoke into the EVAP system.
4. Verify that smoke is not exiting the entire EVAP system with the J 41413-SPT .

⇒ | If smoke is observed, repair the condition as necessary.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Evaporative Emission Canister Vent Solenoid Valve Replacement

• | Evaporative Emission Canister Replacement

• | Evaporative Emission Canister Purge Solenoid Valve Replacement

• | Fuel Sender Assembly Replacement