Got a 97 5.4 and i went to auto zone got my codes pulled p0161 and p1406 the 0161 is for an o2 but which one is it the passanger rear because it says sensor 2 in bank 2, and the 1406 is for EGR position sensor performance but when the autozone kid looked up the sensor there was like 2 of them the presure sensor and something else. i would really like 2 know what sensor that is because my truck doesn't seem to be geting any better gas milage any help would be GREAT

 

I really suggest buying a book from autozone that tells you how to repair our model and year vehicles. I bought one and it showed me how to troubleshoot the EGR and the sensors and everything. Could not have found out the real problem and what was causing it without that book. I know this isn't direct answer to your question but would buy one if you plan on fixing yourself.

 

Do not trust the discriptions these stores give you.
Reason is they are not usually trained techs and the code discriptions are for different engines, years and options and may be for a battle ship for all they know.
Get the codes and come hear.
Code 161 is the heater circuit of the rear ox cat sensor on the drivers side.
This sensor monitors the efficiency of the cat operation. May be as simple as a plugup fault, grounded wire on the exhaust or an open heater element etc.
Code 1406 is a DPFE hose off, cracked or plugged. Just look at it and see what the condition is. The DPFE connects to two small pipes going down to the main tube between the exhaust manifold and the EGR valve on the drivers side of the engine.

 

Hey thatnks for the reply but the thing is I just replaced the DPFE 2 days ago reset my light and it came back on and thats why i went back to az to chech them again and this time i got those 2 codes because before i had 3 different codes. so could the 1406 be for something else maybe cuz i know all my hoses are good coming off the DPFE. Greatly appreciate the reply tho thanks

 

Well all I can tell you is the 1406 code is pretty specific.
It's not a guessing game.
Good luck.

 

Here's the introductory sequence in the applicable PCED:

Diagnostic Trouble Code (DTC) P1406 indicates that Continuous Memory Self-Test has detected the intake manifold side (downstream) differential pressure feedback EGR (D.P.F. EGR) sensor pressure hose is off or plugged.

NOTE:
If the fault is currently present, DTC P1408 will be output in Key On Engine Running (KOER) Self-Test.

Possible causes:

-- Improper downstream pressure hose connection.

-- Downstream pressure hose plugged.

-- Orifice tube assembly loose.

-- Orifice tube assembly broken.

-- Plugged or damaged pressure pickup tubes.

-- Slow responding D.P.F. EGR sensor.

l Key off.

l Inspect downstream hose at D.P.F. EGR sensor and orifice tube assembly for disconnect or poor connection.

l Is hose OFF or poorly connected?

That gives you a little background and an initial first step in properly diagnosing it.

Steve