For 1990-2009 cars
Engine Controls Components
Power, Ground, EVAP, and EGR
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

### Circuit Description

The evaporative emission system is tested by applying vacuum to the EVAP system and monitoring for a vacuum decay. The PCM monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge solenoid valve and the EVAP vent solenoid are turned on, allowing the engine to draw a small vacuum on the entire evaporative emission system. Once the desired vacuum level has been achieved, the EVAP canister purge solenoid valve turns off, sealing the system. A small leak in the system will cause DTC P0442 to set.

The evaporative system includes the following components:

• | The EVAP canister

• | The EVAP canister purge valve

• | The EVAP service port

• | The EVAP vent solenoid

• | The fuel cap

• | The fuel pipes and hoses

• | The fuel tank

• | The fuel tank pressure sensor

• | The fuel vapor lines

• | The purge lines

### Conditions for Running the DTC

• | The following DTCs are not set: P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1621 and P1133.

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

• | The intake air temperature (IAT) is between 5°C and 29°C (41°F- 84°F) at engine start up.

• | The engine coolant temperature (ECT) is between 5°C and 29°C (41°F- 84°F) at engine start up.

• | The IAT is not more than 1°C (2°F) above the ECT at start up.

• | The ECT is not more than 7°C (12°F) above the IAT at start up.

• | The fuel tank level is between 26 percent and 74 percent.

• | The throttle position (TP) angle is between 7 percent and 35 percent.

• | The EVAP solenoid is at 40 percent PWM.

### Conditions for Setting the DTC

The EVAP system is unable to detect a vacuum during the diagnostic test.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

• | A history DTC stores.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs a pass.

• | A history DTC will clear after 40 consecutive warm up cycles without a malfunction.

• | Use a scan tool to clear the DTCs.

### Diagnostic Aids

Although this DTC is considered a type A diagnostic, the DTC acts like a type B diagnostic under certain conditions. Whenever this diagnostic reports that the system has passed, or if the battery is disconnected, the diagnostic must fail twice before setting a DTC. The initial failure does not report to the diagnostic executive or display on a scan tool. A passing system always reports to the diagnostic executive immediately.

If a DTC P0460, P0461, P0462 or P0463 is set along with an EVAP System DTC, the EVAP DTC cannot be considered valid until you repair and clear the DTC P0460, P0461, P0462 or P0463.

Inspect the following components for the indicated conditions:

• | The fuel vapor and the EVAP purge line canister fittings for missing or damaged O-rings.

• | Inspect the PCM harness connectors for the following conditions:

- | Any backed out terminals

- | Any incorrect mating

- | Any broken locks

- | Any incorrectly formed connectors

- | Any damaged terminals

- | A poor terminal-to-wire connection

• | Inspect the wiring harness to the following components for an intermittent open or short:

- | The EVAP vent solenoid

- | The EVAP canister purge valve

- | The fuel tank pressure sensor

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. If an electrical malfunction is present in the vent solenoid or the EVAP canister purge valve , the purge system will not operate correctly. Repairing the electrical malfunction will likely correct the condition that set DTC P0442.

2. This step tests the fuel tank pressure sensor at the ambient pressure.

3. This step verifies that the fuel tank pressure sensor accurately reacts to the EVAP system pressure changes.

4. This step ensures proper system integrity.

#### DTC P0442-Evaporative Emission (EVAP) Control System - Small Leak Detected

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Are DTC P0452, P0453, P0460, P0461, P0462 or P0463 set? | -- | Go to Diagnostic Trouble Code (DTC) List/Type | Go to Step 3
3 | With the scan tool, command the EVAP canister purge valve and the vent solenoid on and off. Do the purge valve and the vent solenoid click on and off? | -- | Go to Step 4 | Go to Powertrain Control Module Outputs Diagnosis
4 |

1. Turn off the ignition.
2. Disconnect the fuel tank vapor line at the EVAP canister.
3. Turn on the ignition, with the engine off.
4. With the scan tool, observe the Fuel Tank Pressure sensor value .

Does the fuel tank pressure equal the specified value?

-0.32 - +0.32 kPa (-1.28 - +1.28 in. H2O)

Go to Step 6

Go to Step 5

5 |

1. Turn off the ignition.
2. Inspect the vapor line from the fuel tank to the EVAP canister for obstructions.
3. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 14

Go to DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage or DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage

6 | Important: : Before continuing with this diagnosis, zero the EVAP Pressure and Vacuum gauges on the J 41413 EVAP pressure/purge diagnostic station. Read the temperature variation instructions and refer to the tool operating instructions.

1. Reconnect the fuel tank vapor line.
2. Connect the J 41413 EVAP pressure/purge diagnostic station to the EVAP service port.
3. With the scan tool, command the EVAP vent solenoid on.

Important:: Do not exceed the pressure given in the first specified value.

4. Pressurize the EVAP system to the first specified value. Monitor the pressure by using the gauge on the station with the switch in the HOLD position.
5. With the scan tool, observe the fuel tank pressure.

Does the fuel tank pressure equal the second specified value?

1.25 kPa (5 in. H2O)

.96 kPa (3.85 in. H2O)

Go to Step 7

Go to DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage or DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage

7 | Important: Review the temperature variation instructions included with the J 41413 EVAP pressure/purge diagnostic station before performing this step.

1. Command the EVAP vent solenoid on with the scan tool.

Important: Do not exceed the pressure given in the first specified value.

2. Pressurize the EVAP system to the first specified value by using the J 41413 EVAP pressure/purge diagnostic station. Monitor the pressure by using the gauge on the station.
3. Move the rotary switch to HOLD and observe the EVAP pressure gauge.

Does the pressure decrease to less than the second specified value within 2 minutes?

3.74 kPa (15 in. H2O)

2.49 kPa (10 in. H2O)

Go to Step 9

Go to Step 8

8 | Important:: Review the temperature variation instructions included with the J 41413 EVAP pressure/purge diagnostic station before performing this step.

1. Turn off the ignition.
2. Install the J 41415-40 fuel tank cap adapter.
3. Connect the J 41413 EVAP pressure purge diagnostic station to the fuel tank cap adapter
4. Turn on the ignition, with the engine off.
5. With the scan tool, command the EVAP System Seal function on.

Important:: Do not exceed the pressure given in the first specified value.

6. Pressurize the EVAP system to the first specified value. Monitor the pressure by using the gauge on the station.

Does the pressure decrease to less than the second specified value within 2 minutes?

3.74 kPa (15 in. H2O)

2.49 kPa (10 in. H2O)

Go to Step 12

Go to Diagnostic Aids

9 |

1. Disconnect the following lines from the EVAP canister.

• | The EVAP purge line

• | The fuel tank vapor line

2. Cap the fuel tank vapor line fitting on the canister.
3. Connect a hand vacuum pump to the EVAP purge line fitting on the canister.
4. Ensure that the EVAP vent solenoid is still commanded on.
5. Apply vacuum to the canister.

Can the specified value be reached and held?

16.95 kPa (5 in. Hg)

Go to Step 12

Go to Step 10

10 |

1. Turn off the ignition.
2. Visually and physically inspect for a disconnected or damaged vent hose and a damaged EVAP canister.
3. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11 |

Notice: The EVAP canister may have released carbon particles which caused this part to fail and may cause damage to other components. Check the EVAP canister for loose carbon before returning the vehicle to service.

1. Replace the EVAP vent solenoid. Refer to Evaporative Emission Vent Valve Replacement .
2. If carbon particles are found in the component, refer to Evaporative Emission System Cleaning .

Did you complete the replacement?

--

Go to Step 13

--

12 |

1. Turn off the ignition.
2. Visually and physically inspect for the following conditions:

• | A malfunctioning fuel cap

• | An incorrect fuel cap

• | A leaking fuel tank filler neck

• | A leaking fuel tank vapor line

• | A damaged EVAP purge line

3. If a problem is found, repair as necessary.
4. Reconnect the previously disconnected lines.
5. Turn on the ignition, with the engine off.
6. With the scan tool, command the EVAP vent solenoid on.
7. With the J 41413 EVAP pressure/purge diagnostic station connected to the EVAP service port, pressurize the EVAP system to the specified value.
8. Use the J 41416 ultrasonic leak detector to locate the leak in the EVAP system. It may be necessary to partially lower the fuel tank in order to examine the connections at the top.
9. Repair as necessary.

Did you complete the repair?

1.25 kPa (5 in. H2O)

Go to Step 14

--

13 | Important:: Review the temperature variation instructions included with the J 41413 EVAP pressure/purge diagnostic station before performing this step.

1. Reconnect all the EVAP hardware that was previously disconnected.
2. Turn on the ignition, with the engine off.
3. With the scan tool command the EVAP vent solenoid on.

Important: Do not exceed the pressure in the first specified value.

4. Pressurize the EVAP system to the first specified value. Monitor the pressure by using the gauge on the station.
5. Switch the rotary switch on the station to HOLD and observe the EVAP pressure gauge.

Does the pressure decrease to less than the second specified value within 2 minutes?

3.74 kPa (15 in. H2O)

2.49 kPa (10 in. H2O)

Go to Step 3

Go to Step 14

14 |

1. Use a scan tool to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 3

System OK