DTC Advanced Diagnostics: P04F0
DTC P04F0:Evaporative Emission (EVAP) System Incorrect Purge Flow Detected

General Description


The fuel vapor in the fuel tank is temporarily stored in the evaporative emission (EVAP) canister and drawn into the engine through the EVAP canister purge valve. The powertrain control module (PCM) controls the amount of vapor introduced into the engine by varying the duty cycle of the EVAP canister purge valve according to the condition of the engine.

Purge flow check of boost pressure side:

The EVAP canister purge valve opens normally (EVAP canister purge valve OPEN OK) and detects that the purge flow is normal when the pulse of the EVAP canister purge valve duty cycle is transmitted to the fuel tank pressure (FTP) sensor during purge flow (pulse method).

OK determination: Pulse exists (P145D OK)
P04F0 Purge flow OK
P04DF EVAP canister purge valve stuck Open OK

NG determination: No pulse (P145D NG)
Either purge flow P04F0 abnormality or P04DF EVAP canister purge valve OPEN failure
In this case, if purge flow check of negative pressure side P0441 is determined as OK or P04DF is determined as OK by the check after the vehicle condition is turned to the OFF (LOCK) mode after P0441 is determined as NG, the purge flow check of boost pressure side P04F0 is determined as NG

When P04DF is determined as OK after the vehicle condition is turned to the OFF (LOCK) mode, P04F0 is also determined after the vehicle condition is turned to the OFF (LOCK) mode.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Once per driving cycle
Sequence
P145D is judged as NG
Duration
10 seconds or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine coolant temperature [ECT SENSOR 1] before EVAP purge control starts
131 °F (55 °C)
–
MAP value [MAP SENSOR]
14 kPa (100 mmHg, 4 inHg)
–
Boost pressure
14 kPa (100 mmHg, 4 inHg)
–
12 volt battery voltage [BATTERY]
10.5 V
–
EVAP canister purge valve duty [EVAP PC DUTY]
40 %
60 %
Fuel trim
0.75
1.47
Fuel feedback
Closed loop at stoichiometric
[ ]: HDS Parameter

Malfunction Threshold
P145D is determined as NG and P04DF is determined as OK.

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 closed stuck
EVAP canister purge valve open stuck
Leak detction pressure sensor output stuck
EVAP system line clogged
EVAP system line misinstalled

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.
Let the engine idle for at least 55 seconds.
3.
Drive the vehicle at high load for total of at least 11 seconds.
4.
Turn the vehicle to the OFF (LOCK) mode and leave the vehicle for at least 10 seconds.
With the HDS
Select the EVAP TEST in the INSPECTION MENU, then select the FUNCTION TEST with the HDS.

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.