DTC P04AB
DTC P04AB: Evaporative Emission (EVAP) Canister Purge Valve Circuit Malfunction 2
General Description
Evaporative emission (EVAP) canister purge valve 2 is attached to the vacuum port between the intake manifold and the EVAP canister. When the engine coolant temperature is a specified value or less, or the output of EVAP canister purge valve 2 is not fully opened, the powertrain control module (PCM) turns off EVAP canister purge valve 2. The PCM adjusts the amount of fuel vapor sent to the engine by controlling EVAP canister purge valve 2 and the EVAP canister purge valve 2 duty cycle. When the return signal does not change according to the EVAP canister purge valve 2 output for a set time, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1.5 seconds or more*2.0 seconds or more**, *** |
| DTC Type | Two drive cycles, MIL on |
| OBD Status | PASSED/FAILED/NOT COMPLETED (STILL TESTING) |
*: Symptom 1
**: Symptom 2
***: Symptom 3
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery] | 10.0 V | - |
| EVAP canister purge valve 2 output duty* | 2 % | 98 % |
| EVAP canister purge valve 2 output duty** | 0 % | |
| EVAP canister purge valve 2 output duty*** | 100 % | |
| State of the engine | Running | |
[ ]: HDS Parameter
Malfunction Threshold
One of these symptom occurs:
- Symptom 1
The return signal does not change according to the EVAP canister purge valve 2 output for at least 1.5 seconds.
- Symptom 2
When the return signal is fully opened and continues for at least 2.0 seconds while the EVAP canister purge valve 2 output is 0 % (totally closed).
- Symptom 3
When the return signal is fully closed and continues for at least 2.0 seconds while the EVAP canister purge valve 2 output is 100 % (totally opened).
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 purge valve 2 PCS2 line open
- EVAP canister purge valve 2 PCS2 line short to ground
- EVAP canister purge valve 2 power supply line open
- 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 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.