DTC P2421
DTC P2421: EVAP Canister Vent Shut Valve Stuck Open
General Description
The powertrain control module (PCM) can only detect if the evaporative emission (EVAP) canister vent shut valve is stuck open if it is commanded close because this is a normally opened valve. When the EVAP canister vent shut valve is commanded closed during the purge, the fuel tank pressure (FTP) sensor value lowers due to the decompression of the EVAP system. If the FTP sensor value does not lower, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Once per driving cycle |
| Sequence | None |
| Duration | 3.5 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Soak duration* | 6 hours | - |
| *1: 6-Speed A/T *2: 9-Speed A/T *: Cancels detection if out of condition **: Condition to permit monitor intake air temperature ***: Condition to start purge ****: Condition to permit total up intake air amount [ ]: HDS Parameter |
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after the vehicle condition is turned to the ON mode | 1 second | - |
| Elapsed time after starting the engine (after soak)** | 10 seconds | - |
| Outside air temperature* | 40.0°F (4.4 °C) | - |
| Engine coolant temperature [ECT Sensor]*** | 140 °F (60 °C)* 1122 °F (50 °C)* 2 | - |
| Engine coolant temperature (at radiator) after soak* | 40.0 °F (4.4 °C) | - |
| Engine coolant temperature (at engine) lowering from after soak to current* | - | 9 °F (5 °C) |
| Engine coolant temperature (at radiator) lowering from after soak to current* | - | 3 °F (2 °C) |
| Vehicle speed [VEHICLE SPEED]**** | 25 mph (39 km/h) | - |
| 12 volt battery voltage [BATTERY] | 10.5 V | - |
| Total intake air amount | 680 g (23.98 oz) | - |
| Intake air amount**** | 7.63 g/second (0.2691 oz/second) | - |
| Purge duty [PCS DUTY] | 20 % | - |
| EVAP canister vent shut valve command | Close | |
| *1: 6-Speed A/T *2: 9-Speed A/T *: Cancels detection if out of condition **: Condition to permit monitor intake air temperature ***: Condition to start purge ****: Condition to permit total up intake air amount [ ]: HDS Parameter |
Malfunction Threshold
The FTP sensor value change is -0.19 kPa (-1.5 mmHg, -0.05 inHg) or less.
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- EVAP canister vent shut valve stuck open
Confirmation Procedure
Operating Condition
- 1.
Start the engine. Hold the engine speed [Engine Speed] at 3, 000 rpm without load (in P or N) until the radiator fan comes on.
- 2.
Turn the vehicle to the OFF (LOCK) mode and leave the vehicle for at least 6 hours.
- 3.
Start the engine. Hold the engine speed [Engine Speed] at 3, 000 rpm without load (in P or N) until the radiator fan comes on.
- 4.
Let it idle for at least 5 minutes 45 seconds.
- 5.
Drive the vehicle at 25 mph (40 km/h) or more under light load only.
- When you have difficulty duplicating the DTC because of road conditions and traffic situations, repeat the driving pattern several times.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool clear command or by disconnecting the 12 volt battery.