P2420
DTC P2419 Evaporative Emission System Switching Valve Control Circuit LowDTC P2420 Evaporative Emission System Switching Valve Control Circuit High
DTC Detection Condition:
DTC SUMMARY
DESCRIPTION
While the engine is running, if a predetermined condition (closed- loop etc.) is met, the EVAP VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the EVAP VSV to control purge flow volume.
The purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when the negative pressure (vacuum) is applied to the canister. The given two monitors run to confirm appropriate EVAP system operation.
1. Key-off monitor
This monitor checks for Evaporative Emission (EVAP) system leaks and pump module malfunctions. The monitor starts 5 hours* after the engine switch is turned off. More than 5 hours are required to allow the fuel to cool down to stabilize the Fuel Tank Pressure (FTP), thus making the EVAP system monitor more accurate.
The electric vacuum pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system and malfunctions in both the pump module and EVAP VSV, based on the EVAP pressure.
HINT: *If the engine coolant temperature is not below 35 °C 5 hours after the engine switch is turned off, the monitor check starts 2 hours later. If it is still not below 35 °C 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.
2. Purge flow monitor
The purge flow monitor consists of the two monitors. The 1st monitor is conducted every time and the 2nd monitor is conducted if necessary.
- The 1st monitor
While the engine is running and the purge Vacuum Switching Valve (VSV) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change.
If negative pressure is not created, the ECM begins the 2nd monitor.
- The 2nd monitor
The vent valve turned OFF (open) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.5 kPa (3.75 mmHg), the ECM interprets this as the EVAP VSV being stuck closed, and illuminates the MIL and sets DTC P0441 (2 trip detection logic).
Atmospheric pressure check: In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.
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INSPECTION PROCEDURE
NOTE: The intelligent tester is required to conduct the given diagnostic troubleshooting procedure.
HINT:
- Using the intelligent tester monitor results enable the EVAP system to be confirmed.
- Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions (Part 1):
Typical Enabling Conditions (Part 2):
Typical Malfunction Thresholds (Part 1):
Typical Malfunction Thresholds (Part 2):
5 hours* after the engine switch is turned off, the electric vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.
Part 1:
Part 2:
HINT: *If the engine coolant temperature is not below 35 °C (95 °F) 5 hours after the engine switch is turned off, the monitor check starts 2 hours later. If it is still not below 35 °C (95 °F) 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.
HINT: *:If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
1. P2419: Vent valve stuck closed
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The EVAP (Evaporative Emission) system pressure is then measured by the ECM using the pressure sensor to determine the 0.02 inch leak pressure standard. If the pressure exceeds -1.06 kPa (-7.95 mmHg)* 4 seconds after the vacuum pump is turned ON, the ECM interprets this as the vent valve being stuck closed. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The threshold varies according to the atmospheric pressure measured in operation A. The value described is based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
2. P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closes) and the EVAP (Evaporative Emission) system pressure is then measured by the ECM using the pressure sensor to conduct an EVAP leak check. If pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and sets the DTC.
MONITOR RESULT
Refer to CHECKING MONITOR STATUS. Mode 6 Data