DTC P0443
DTC P0443: Evaporative Emission (EVAP) Canister Purge Valve Circuit Malfunction
General Description
The evaporative emission (EVAP) canister purge valve is attached to the vacuum port between the intake manifold and the EVAP canister. The powertrain control module (PCM) does not turn on the EVAP canister purge valve when the engine coolant temperature is less than a specified value. The PCM adjusts the amount of fuel vapor sent to the engine by controlling the EVAP canister purge valve duty cycle. When the return signal does not change according to the EVAP canister purge valve 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 |
*: Symptom 1
**: Symptom 2
***: Symptom 3
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage | 10.0 V | - |
| EVAP canister purge valve output duty | 2 % | 98 % |
| State of the engine | Running | |
| Other**,*** | EVAP canister purge valve output duty is 0 % or 100 % | |
Malfunction Threshold
One of these symptoms occurs:
- Symptom 1
The return signal does not change according to the EVAP canister purge valve 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 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 output is 100 % (totally opened).
Possible Cause
- EVAP canister purge valve PCS line open
- EVAP canister purge valve PCS line short to ground
- EVAP canister purge valve power supply line open
- PCM internal circuit failure
Confirmation Procedure
Operating Condition
Enter the maintenance mode, than 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.
[ ]: HDS Parameter
With the HDS
None.
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.