DTC Advanced Diagnostics: P2401 (3.0L Engine)
DTC P2401: Evaporative Emission (EVAP) Leak Check Pump Control Circuit Low Voltage
General Description
The evaporative emission (EVAP) leak check module vacuum pump absorbs the air in the fuel tank and the EVAP leak check module pressure sensor measures the vacuumed pressure. The powertrain control module (PCM) compares the vacuumed pressure with a reference pressure to detect leaks of the fuel tank. The PCM controls the ON/OFF of the EVAP leak check module vacuum pump. If the VMOTOR terminal voltage level is ON (low voltage) while the PCM outputs OFF signal to the EVAP leak check module vacuum pump, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 0.5 second or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery] | 10.0 V | - |
[ ]: HDS Parameter
Malfunction Threshold
The VMOTOR terminal voltage level is ON (low voltage) for at least 0.5 second while the PCM outputs OFF signal to the EVAP leak check module vacuum pump.
Possible Cause
- EVAP leak check module vacuum pump VMOTOR line short to ground
- EVAP leak check module vacuum pump power supply line short to ground
- PCM internal circuit failure
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, the freeze data, and the on-board snapshot 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, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.