Service Engine Soon Line gives me error P0402

[kizzyhuz1]

What could it be? Is it something I could fix myself and how? Please help...:exporange

 

[ncranchero]

Probably the DPFE sensor. Buy OEM Ford or Motorcraft ONLY.

DPFE sensor test (according to Chilton)

1. Disconnect pressure hoses at the DPFE sensor 2. Connect a hand vacuum pump to the downstream tube marked REF on the sensor. 3. Using a multimeter, back probe the SIG RTN circuit at the DPFE connector. 4. With the ignition ON, Signal voltage should be .2-.7 volts. 5. Apply 8-9in Hg of vacuum to the sensor. Voltage should be greater than 4 volts. 6. Quickly release the vacuum from the sensor. Voltage should drop to less than 1 volt in 3 seconds. 7. If the sensor does not respond as specified, check the power and ground circuits. 8. If power and ground circuits are functional, the sensor is faulty.

 

[t_clealy]

Probably the DPFE sensor. Buy OEM Ford or Motorcraft ONLY.

DPFE sensor test (according to Chilton)

1. Disconnect pressure hoses at the DPFE sensor 2. Connect a hand vacuum pump to the downstream tube marked REF on the sensor. 3. Using a multimeter, back probe the SIG RTN circuit at the DPFE connector. 4. With the ignition ON, Signal voltage should be .2-.7 volts. 5. Apply 8-9in Hg of vacuum to the sensor. Voltage should be greater than 4 volts. 6. Quickly release the vacuum from the sensor. Voltage should drop to less than 1 volt in 3 seconds. 7. If the sensor does not respond as specified, check the power and ground circuits. 8. If power and ground circuits are functional, the sensor is faulty.

Great Post. Great Info. Thank you so much.

 

[BD72]

Mine was doing the same thing. I replaced the sensor and had no problems.