DTC Troubleshooting: P04F1
DTC P04F1: EVAP System Low Purge Flow Detected
Special Tools Required
?Vacuum Pump/Gauge, 0?30 inHg Snap-on YA4000A or equivalent, commercially available
?Vacuum/Pressure Gauge, 0?4 inHg 07JAZ-001000B
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
P04F1 EVAP System Low Purge Flow Detected
    

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Select the EVAP TEST in the INSPECTION MENU, then select the FUNCTION TEST with the HDS.

  

Is the result OK?

     
YES
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot.?
     
NO
     
     
     
The failure is duplicated. Go to step 2.
2.
EVAP canister purge line visual check:

EVAP canister purge line visual check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check for a poor connection, a blockage, or damage at the EVAP canister purge line between the throttle body and the EVAP canister.

Is the line OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Reconnect or repair the EVAP canister purge line.?
3.
Determine possible failure area (EVAP canister purge valve, others):

Determine possible failure area (EVAP canister purge valve, others)
?1.
Remove the EVAP canister purge valve cover.

?2.
Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a T-fitting (C), a vacuum gauge, and a vacuum pump/gauge, 0?30 inHg, to the vacuum hose as shown.


?3.
Turn the vehicle to the ON mode.

?4.
Select the EVAP TEST in the INSPECTION MENU, then select the EVAP PCS ON in the SINGLE SOLENOID with the HDS.

  

?5.
Apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

Does it hold vacuum?

     
YES
     
     
     
     
NO
     
     
     
Go to step 4.
4.
Determine possible failure area (EVAP canister purge line, others):

Determine possible failure area (EVAP canister purge line, others)
?1.
Select the EVAP TEST in the INSPECTION MENU, then select the EVAP PCS OFF in the SINGLE SOLENOID with the HDS.

  

?2.
Reconnect the vacuum hose to the EVAP canister purge valve.

?3.
Remove the right front floor undercover.

?4.
Disconnect the EVAP canister purge line (A) from the canister (B). Connect the T-fitting (C), the vacuum gauge, and the vacuum pump/gauge, 0?30 inHg, to the EVAP canister purge line as shown.


?5.
Apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

?6.
Select the EVAP PCS ON in the SINGLE SOLENOID with the HDS.

  

Does it hold vacuum?

     
YES
     
     
     
Check for a blockage in the purge line between the EVAP canister purge valve and the EVAP canister.?
     
NO
     
     
     
Go to step 5.
5.
FTP sensor performance check:

FTP sensor performance check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Remove the FTP sensor with its connector connected.

?3.
Connect the T-fitting (A) to the vacuum pump/gauge, and the vacuum gauge to the FTP sensor (B) as shown.


?4.
Turn the vehicle to the ON mode.

?5.
Check and record the FTP SENSOR in the DATA LIST with the HDS.
Signal
Current conditions
Values
Unit
FTP SENSOR
    

?6.
Slowly apply about 1.3 kPa (0.4 inHg, 10 mmHg) of vacuum to the hose.
NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.

?7.
Check the FTP SENSOR in the DATA LIST with the HDS.
Signal
Current conditions
Values
Unit
FTP SENSOR
    

Does the value of FTP SENSOR change from the recorded value?

     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
6.
EVAP canister purge line check:

EVAP canister purge line check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Reconnect the EVAP canister purge line to the EVAP canister, and reinstall the FTP sensor.

?3.
Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect the T-fitting (C), the vacuum gauge, and the vacuum pump/gauge, 0?30 inHg, to the vacuum hose as shown.


?4.
Slowly apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

Does the hose hold vacuum?

     
YES
     
     
     
Check for a blockage at the EVAP canister purge line port.?
     
NO