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 provide an overview of each diagnostic category.

### DTC Descriptors

DTC P0442: Evaporative Emissions (EVAP) System Small Leak Detected
DTC P0456: Evaporative Emissions (EVAP) System Very Small Leak Detected

### Circuit/System Description

This DTC tests the evaporative emission (EVAP) system for a small leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge solenoid valve ON and the EVAP vent solenoid valve ON. This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the EVAP canister purge solenoid valve OFF, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum decay. If the control module detects a leak larger than a calibrated amount, these DTCs will set.

### Conditions for Running the DTC

• | DTCs P000A, P000B, P0010, P0013, P0016, P0017, P0030, P0031, P0032, P0068, P0072, P0073, P0074, P009A, P0101, P0102, P0103, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0171, P0172, P0201, P0202, P0203, P0204, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0341, P0365, P0366, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0456, P0458, P0459, P0496, P0498, P0499, P0501, P0506, P0507, P0562, P0563, P0601, P0603, P0604, P0605, P0606, P0607, P061A, P061B, P061C, P0642, P0643, P1101, P2088, P2089, P2090, P2091, P2100, P2101, P2119, P2176, P2227, P2228, P2297, P2301, P2304, P2307, P2310, P2610, and P2A00 are not set.

• | The ignition is ON.

• | The barometric pressure (BARO) is more than 75 kPa.

• | The engine coolant temperature (ECT) is less than 110°C (230°F).

• | The engine has been running between 1-10 minutes.

• | The engine is idling.

• | The fuel level is between 6-40 liters (2-10 gallons).

• | The fuel tank pressure (FTP) is between -3 and +1 kPa (-12 and +4 in H2O).

• | The vehicle speed is 0 kph (0 mph).

• | The intake air temperature (IAT) is between -8 and +70°C (+17 and +158°F).

• | The battery voltage is more than 10 volts.

• | The engine is operating in Closed Loop fuel control.

• | DTC P0442 and P0456 run once per drive cycle when the above conditions have been met.

### Conditions for Setting the DTC

• | DTC P0442 sets when a leak greater than 0.85 mm (0.033 in) is detected.

• | DTC P0456 sets when a leak between 0.85-0.39 mm (0.033-0.015 in) is detected.

### Action Taken When the DTC Sets

DTCs P0442 and P0456 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0442 and P0456 are Type B DTCs.

### Diagnostic Aids

• | The EVAP system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. For example, when injecting smoke at the purge tube, remove the filler cap or temporarily leave the vent open until smoke is observed. Close the system and continue testing. If using a fuel cap adapter at the filler neck, disconnect the purge tube at the EVAP canister purge solenoid valve until smoke is observed.

• | To help locate intermittent leaks, use the J 41413-200 (J 41413-100) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with a high intensity white light.

• | To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with a high intensity white light.

• | If a small leak is difficult to find, it may be necessary to remove the EVAP components and test them one at a time using the adapters in the J 41413-300 .

### Reference Information

#### Schematic Reference

Evaporative Emissions Hose Routing Diagram

#### Description and Operation Reference

Evaporative Emission Control System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

• | CH-48096 EVAP Service Access Port Tool

• | GE-41415-50 Fuel Tank Cap Adapter

• | J 41413-200 (J 41413-100) Evaporative Emission System Tester (EEST)

• | J 41413-311 EVAP Plug

• | J 41413-300 EVAP Cap and Plug Kit

### Circuit/System Testing

Important:

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

• | Refer to J 41413-200 (J 41413-100) operation manual for detailed instructions in Evaporative Emission System Diagnosis.

1. Disconnect the purge tube at the EVAP canister side of the EVAP canister purge solenoid valve and install the J 41413-311 brass cone adapter.
2. Connect the J 41413-200 (J 41413-100) nitrogen/smoke hose to the J 41413-311 brass cone adapter.
3. Disconnect the EVAP vent pipe from the EVAP canister vent solenoid valve.
4. Seal the EVAP vent pipe using a plug from the J 41413-300 .
5. Use the flow meter on the J 41413-200 (J 41413-100) calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.

⇒ | If a leak is detected, use the J 41413-200 (J 41413-100) to apply smoke to the EVAP system at the purge tube or the filler neck until the leak is located.

### Repair Instructions

Clear the DTCs with a scan tool.

### Repair Verification

1. Seal the system and use the flow meter on the J 41413-200 (J 41413-100) calibrated to 0.51 mm (0.020 in) to determine that there are no leaks in the EVAP system.
2. Perform the Diagnostic Repair Verification after completing the diagnostic procedure.