several DTCs
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Cargo Master
Joined: Mar 2008
Posts: 2,409
Likes: 1
From: Goliad, Texas
several DTCs
a guy I know has a 2003 F150 2wd with a 5.4. he wanted me to look at it since the CEL is on. I'm getting P0171, P0174, and P0405. the lean codes I can't understand. no vacuum leaks, all hoses look good, nothing broke or anything, then the P0405. he has replaced the hose that always breaks that comes off of the PCV valve and cleaned the MAF sensor before. I'm at a loss on this one. it's literally making me scratch my head. anyone have any ideas on this? does the P0405 have anything to do with these other codes?
any help would be greatly appreciated....
any help would be greatly appreciated....
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
For 171/174 codes, verify with a Scanner the long term fuel table values.
If 25% or more out of limits there is an air leak causing it.
This is detected by the OX sensors so there is no doubt about what the cause is. The sensors detect excessive Ox (to lean) in the exhaust gas.
The 405 code is an EGR code for an 'electrical failure' to the DPFE.
Check the description for the code.
There is no normal relationship between the 171/174 codes and 405 unless it's mechanical and indirectly caused by work done in the engine bay.
Check to see if the DPFE plug is seated. It could be a DPFE or harness failure.
Good luck.
If 25% or more out of limits there is an air leak causing it.
This is detected by the OX sensors so there is no doubt about what the cause is. The sensors detect excessive Ox (to lean) in the exhaust gas.
The 405 code is an EGR code for an 'electrical failure' to the DPFE.
Check the description for the code.
There is no normal relationship between the 171/174 codes and 405 unless it's mechanical and indirectly caused by work done in the engine bay.
Check to see if the DPFE plug is seated. It could be a DPFE or harness failure.
Good luck.
Thread Starter
|
Cargo Master
Joined: Mar 2008
Posts: 2,409
Likes: 1
From: Goliad, Texas
For 171/174 codes, verify with a Scanner the long term fuel table values.
If 25% or more out of limits there is an air leak causing it.
This is detected by the OX sensors so there is no doubt about what the cause is. The sensors detect excessive Ox (to lean) in the exhaust gas.
The 405 code is an EGR code for an 'electrical failure' to the DPFE.
Check the description for the code.
There is no normal relationship between the 171/174 codes and 405 unless it's mechanical and indirectly caused by work done in the engine bay.
Check to see if the DPFE plug is seated. It could be a DPFE or harness failure.
Good luck.
If 25% or more out of limits there is an air leak causing it.
This is detected by the OX sensors so there is no doubt about what the cause is. The sensors detect excessive Ox (to lean) in the exhaust gas.
The 405 code is an EGR code for an 'electrical failure' to the DPFE.
Check the description for the code.
There is no normal relationship between the 171/174 codes and 405 unless it's mechanical and indirectly caused by work done in the engine bay.
Check to see if the DPFE plug is seated. It could be a DPFE or harness failure.
Good luck.
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