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 intake manifold 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 line, others):

Determine possible failure area (EVAP canister purge line, others)
?1.
Remove the EVAP canister purge valve with its connector and vacuum hose connected.

?2.
Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B).


?3.
Disconnect the EVAP canister purge line (A) from the EVAP 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.


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

Does the hose hold vacuum?

     
YES
     
     
     
Check for a blockage in the EVAP purge line between the EVAP canister purge valve and the EVAP canister.?
     
NO
     
     
     
Go to step 4.
4.
EVAP canister purge valve check:

EVAP canister purge valve check
?1.
Inspect the EVAP canister purge valve.

Is the EVAP canister purge valve OK?

     
YES
     
     
     
Go to step 5.
     
NO
     
     
     
5.
Purge tube check:

Purge tube check
?1.
Connect the vacuum pump/gauge, 0?30 inHg, to the purge tube (A) as shown.


?2.
Start the engine, and let it idle.

Is there vacuum?

     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
Check for blockage at the purge tubes between the intake manifold and the EVAP canister purge valve.?
6.
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, 0?30 inHg, 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 reading 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 change?

     
YES
     
     
     
Go to step 7.
     
NO
     
     
     
7.
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