SPONSORED LINKS

P0401 after O2 sensor replacement

Tiny
STXHAMMER
  • MEMBER
  • 2002 FORD EXPLORER
  • 4.0L
  • 6 CYL
  • AUTOMATIC
  • 166,000 MILES
Hello, I recently replaced by driver side bank 2 o2 sensor. Now I am showing P0401 code. Also upon acceleration there’s a whining sound almost like a super charger sound. Is it the EGR? Or a loose hose? I have picked up some carbon cleaner also and plan on doing that also. I will be back home this weekend to search for a vacuum leak if it’s that. Thank you in advance.
SPONSORED LINKS
Friday, December 14th, 2018 AT 11:42 PM

11 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

The 401 code is for the DPFE sensor. It is n exhaust back pressure sensor.

Was there a code prior to this that made you think the sensor was bad?

Roy

401 possible issues

P0401
Descriptor
Egr Flow Insufficient Detected
Probable Causes
Differential Pressure Feedback EGR (DPFE) Sensor Downstream Hose Off or Plugged
Differential Pressure Feedback EGR (DPFE) Sensor Hoses Both Off
Differential Pressure Feedback EGR (DPFE) Sensor Hoses Reversed
EGR Vacuum Regulator (EGRVR) Circuit Shorted to Power
EGR Vacuum Regulator (EGRVR) Solenoid Damaged
EGR Vacuum Regulator (EGRVR) solenoid Circuit Open to Powertrain Control Module (PCM)
Exhaust Gas Recirculation (EGR) Flow Restricted
Exhaust Gas Recirculation (EGR) Orifice Tube Damaged
Exhaust Gas Recirculation (EGR) Solenoid
Exhaust Gas Recirculation (EGR) Valve
Exhaust Gas Recirculation (EGR) Valve Leak Vacuum
Exhaust Gas Recirculation (EGR) Valve Stuck Closed
Powertrain Control Module (PCM)
Powertrain Control Module (PCM) Damaged
Reference Voltage from Powertrain Control Module (PCM) Open to Differential Pressure Feedback EGR (DPFE) Sensor
Vacuum Supply
Voltage Power Open to EGR Vacuum Regulator (EGRVR) Solenoid
Images (Click to make bigger)
Thumb
Thumb
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 7:55 AM
Tiny
STXHAMMER
  • MEMBER
  • 45 POSTS
If you’re talking about the o2 sensor, it had the P0156 code.
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 8:41 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, did you do any of these checks or just replace the sensor?

Roy

P0156
Descriptor
Ho2S Sensor Circuit Malfunction (Ho2S-22)
Probable Causes
Exhaust Leaks
Sensor Contaminated or Damaged
Sensor Wires Crossed
Wiring and Pins Pinched, Shorted, or Corroded
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 8:45 AM
Tiny
STXHAMMER
  • MEMBER
  • 45 POSTS
Replaced it. The wiring was melted.
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 11:43 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good. I would replace the DPFE sensor.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 2:06 PM
Tiny
STXHAMMER
  • MEMBER
  • 45 POSTS
Would you happen to have the location of it. Passenger side of the motor I assume. And plug and play?
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 2:40 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
It is on top of the motor behind the throttle body. It has two rubber hoses that go to the exhaust manifold.

It is a plug and play replacement.

Roy
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Saturday, December 15th, 2018 AT 5:26 PM
Tiny
STXHAMMER
  • MEMBER
  • 45 POSTS
It seems my DPFE sensor is stuck on there. May try some wd40 on the hoses. Is that safe or no?
Was this
answer
helpful?
Yes
No
Wednesday, December 19th, 2018 AT 1:12 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Yes, you can but if you damage them, replace them. They are special hoses due to the heat from the exhaust.

Roy
Was this
answer
helpful?
Yes
No
Wednesday, December 19th, 2018 AT 1:22 PM
Tiny
STXHAMMER
  • MEMBER
  • 45 POSTS
Okay, thanks. I’ll try without it again tomorrow. Thanks
Was this
answer
helpful?
Yes
No
Wednesday, December 19th, 2018 AT 1:59 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

We are always glad to help.

Roy
Was this
answer
helpful?
Yes
No
-1
Wednesday, December 19th, 2018 AT 2:00 PM

Please login or register to post a reply.

Related Oxygen Sensor Replace/Remove Content

Oxygen Sensor Replacement
VIDEO
Oxygen Sensor Replacement
Instructional repair video
Oxygen Sensor Replacement
GUIDE
Oxygen Sensor Replacement
An oxygen or lambda sensor is used to determine the engine exhaust mixture which can then be controlled by the computer. These sensors are equipped with a heater that can...
VIEW MORE

Sponsored links