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 00: Evaporative Emissions (EVAP) System Small Leak Detected
DTC P0456 00: Evaporative Emissions (EVAP) System Very Small Leak Detected

### Circuit/System Description

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

### Conditions for Running the DTC

• | DTCs P000A 00, P000B 00, P0010 00, P0013 00, P0016 00, P0017 00, P0030 00, P0031 00, P0032 00, P0111 00, P0112 00, P0113 00, P0114 00, P0117 00, P0118 00, P0119 00, P0121 00, P0122 00, P0123 00, P0131 00, P0132 00, P0133 00, P0134 00, P0135 00, P0171 00, P0172 00, P0201 00, P0202 00, P0203 00, P0204 00, P0221 00, P0222 00, P0223 00, P0261 00, P0262 00, P0264 00, P0265 00, P0267 00, P0268 00, P0270 00, P0271 00, P0300 00, P0301 00, P0302 00, P0303 00, P0304 00, P0335 00, P0336 00, P0340 00, P0341 00, P0365 00, P0366 00, P0442 00, P0443 00, P0446 00, P0451 00, P0452 00, P0453 00, P0454 00, P0455 00, P0456 00, P0458 00, P0459 00, P0496 00, P0498 00, P0499 00, P0501 00, P0506 00, P0507 00, P0562 00, P0563 00, P0601 00,P0602 00, P0604 00, P0606 00, P0607 00, P061A 00, P0642 00, P0643 00, P2088 00, P2089 00, P2090 00, P2091 00, P2100 00, P2101 00, P2119 00, P2176 00, P2297 00, P2301 00, P2304 00, P2307 00, P2310 00, P2610 00, and P2A00 00 are not set.

• | The barometric pressure (BARO) is more than 75 kPa (11 PSI).

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

• | The engine is idling.

• | The fuel level is between 6-40 L (2-10 gal).

• | The fuel tank pressure is between -3 kPa and +1 kPa (-0.4 PSI and +0.1 PSI).

• | The vehicle speed is 0 km/h (0 mph).

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

• | The battery voltage is more than 10 V.

• | The engine is operating in closed loop fuel control.

• | DTC P0442 00 and P0456 00 run once per drive cycle when the above conditions have been met.

### Conditions for Setting the DTC

• | DTC P0442 00 sets when a leak greater than 0.85 mm (0.033 in) is detected.

• | DTC P0456 00 sets when a leak between 0.85-0.39 mm (0.033-0.015 in) is detected.

### Action Taken When the DTC Sets

DTCs P0628 00 and P0629 00 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0442 00 and P0456 00 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 EN-41413-200 Emissions System Tester (EEST) 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 EN-41413-300 EVAP Cap and Plug Kit .

### Reference Information

#### Schematic Reference

NEED LINK (Evaporative Emission Hose Routing Diagram)

#### Description and Operation Reference

Evaporative Emission Control System Diagnosis

#### 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

EN-41413-300 EVAP Cap and Plug Kit

EN-41413-200 Emissions System Tester (EEST)

EN-41413-SPT High Intensity White Light

For equivalent regional tools, refer to Special Tools.

### Circuit/System Testing

• | 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.

• | Refer to the EN-41413-200 Emissions System Tester (EEST) operation manual for detailed instructions

1. Connect the EN-41413-200 Emissions System Tester (EEST) to the vehicle at the EVAP service port. For vehicles without a service port, disconnect the purge tube at the quick connector on the EVAP canister side of the Q12 Evaporative Emission (EVAP) Canister Purge Solenoid Valve and install the CH-48096 EVAP Service Access Port Tool .
2. Using a scan tool, close the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve to seal the EVAP system.
3. Use the flow meter on the EN-41413-200 Emissions System Tester (EEST) , 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 EN-41413-200 Emissions System Tester (EEST) to apply smoke to the EVAP system at the service port or the purge tube until the leak is located using the EN-41413-SPT High Intensity White Light .

### Repair Instructions

1. Seal the EVAP system and use the flow meter on the EN-41413-200 Emissions System Tester (EEST) , calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
2. Clear DTCs.