System Description
The diagnostic strategy for the evaporative emission (EVAP) system uses a vacuum pump to test for system leaks, after the engine is OFF. A unique fuel tank, EVAP canister, and EVAP vacuum leak pump work together to provide enhanced system diagnosis. The vacuum leak pump, the fuel tank pressure (FTP) sensor and the EVAP canister vent valve are all integral parts of one assembly. The assembly is attached directly to the EVAP canister, located near the fuel tank.
After the vehicle has sat with the engine OFF for at least 5 hours and the engine coolant temperature is less than 35°C (95°F), a comprehensive diagnostic is enabled. The complete diagnostic test can take up to 15 minutes to run, with leak detection comprising the largest portion of the test. For more detailed information on the EVAP system components and diagnostic strategy, refer to Evaporative Emission Control System Description .
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P043F Evaporative Emission (EVAP) System Reference Orifice Flow Excessive
Conditions for Running the DTC
| • | DTC P0110, P0112, P0113, P0115, P0117, P0118, P0450, P0451, P0452, P0453, P2610 are not set. |
| • | Five hours have elapsed after the engine was turned OFF. |
| • | Atmospheric pressure is between 70-110 kPa. |
| • | Battery voltage is more than 10.5 volts. |
| • | Engine coolant temperature is between 4-35°C (40-95°F). |
| • | Intake air temperature is between 4-35°C (40-95°F). |
| • | The ignition remains OFF for the duration of the test. |
| • | DTC P043F runs once per drive cycle when the above conditions are met. |
Conditions for Setting the DTC
The PCM has determined there is too much flow through the reference orifice of the EVAP vacuum leak detection pump.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present. |
| • | A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault. |
| • | A DTC can be cleared by using the scan tool Clear Information function. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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In order to correctly identify the malfunction, DTC P2401, P2402, and P2419 must be diagnosed before DTC P043E or P043F.
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This step uses the EVAP Service Bay test to verify the correct operation of the EVAP vent solenoid, the EVAP purge solenoid, and the EVAP vacuum leak pump. Using the Service Bay test also tests for leaks by sealing the system and monitoring the FTP sensor.
Step | Action | Yes | No | ||||
|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | |||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||
Inspect for additional evaporative emission (EVAP) system DTCs.
Are any other EVAP system DTCs set? | Go to Step 3 | ||||||
3 |
Did you find and correct the condition? | Go to Step 5 | Go to Step 4 | ||||
4 | Replace the EVAP vacuum leak pump assembly. Refer to Evaporative Emission System Vacuum Leak Pump Replacement . Did you complete the replacement? | Go to Step 5 | -- | ||||
Did you complete the EVAP Service Bay Test? | Go to Step 6 | -- | |||||
6 |
Are there any DTCs that have not been diagnosed? | System OK | |||||
