DTC Advanced Diagnostics: P24BF (3.0L Engine)
DTC P24BF: Evaporative Emission (EVAP) Leak Check Module Canister Change Over Valve Control Circuit High Voltage
General Description
The canister change over valve in the evaporative emission (EVAP) leak check module is a valve that switches the air absorbing destination of the EVAP leak check module vacuum pump between the fuel tank side and the reference orifice side. When the canister change over valve is switched to the reference orifice side, the EVAP leak check module vacuum pump absorbs the air in the reference orifice side and determines the reference pressure for fuel tank leak detection. After the reference pressure is determined, the canister change over valve is switched to absorb the air in the fuel tank side. The pressure of the fuel tank side is measured by the EVAP leak check module pressure sensor and it is compared with the reference pressure to detect leaks of the fuel tank. The powertrain control module (PCM) controls the ON/OFF of the canister change over valve. If the CCV_GND terminal voltage level is OFF (high voltage) while the PCM outputs ON signal to the canister change over valve, 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 CCV_GND terminal voltage level is OFF (high voltage) for at least 0.5 second while the PCM outputs ON signal to the canister change over valve.
Possible Cause
- Canister change over valve CCV_GND line short to power
- 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.