P0401 & P0133 Codes

[sslaymon]

I've got a 2002 with the 4.0l and had the SES light randomly pop up. Took it to a parts store, codes came up were P0401 & P0133. Would a certain one typically cause one to go out first?

Been looking to see if the DPFE would cause it to throw the P0133 code or the bad O2 sensor to throw the P0401 code? Any ideas would help.

Thanks,

Shawn

 

[AlexP978]

p0133 O2 Sensor Circuit Slow Response Bank 1 Sensor 1
Possible causes could be a faulty upstream oxygen sensor, faulty fuel injectors, or there could be a air or exhaust leak somewhere.

Look at Replacing the Front Heated Oxygen Sensor Bank 1 usually takes care of the problem

Read more: http://engine-codes.com/p0133_ford.html#ixzz2IlOTpnNO

as for the p0401 code, try cleaning the EGR valve and its tubes and passages. If everything is clean, it is possible the EGR valve is malfunctioning

 

[esclamada]

Try fixing it one at a time, sometimes these errors are related to each other, fixing one will fix the other.
Most of the time p0401 is the EGR pressure sensor, it can be replaced by cheap aftermarket sensors.

p0133 sometimes indicate that the O2 sensor needs to be replaced. Do this after the p0401 is fixed (if it shows up)


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[sslaymon]

I pulled the EGR valve off and cleaned it up. It wasn't very dirty at all for 126k miles on it. Looks like I'll go buy the O2 sensorfirst and have a couple cycles ran to see if the code clears. Do you think the sensor going out(P0133) would cause the P0401 code to be thrown though? Or they just happen to go out at the same time?


O2 sensor in a reasonable spot to get to? Is it pretty close to the heads or tucked away pretty easy? Also, is bank 1 the driver's side or the passenger's side? Don't want to mess up and replace the wrong one.

I know my old Grand Prix before this was a PITA to get to.

 

[esclamada]

I think they are easy to get into underneath, last time I checked they are clearly visible and has some space to work on (I have a 4.6 so I'm not sure if there's a difference between 4.0)

IMO Oxygen sensors are replaced last, I can't say that they are related with the p0401 code but oxygen sensors rarely fails.


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[AlexP978]

if you can get underneath the truck, look where the cats are. there is one before and one after each cat. they are very easy to get to. bank 1 should be the passenger side.

i'm not sure if the o2 sensor could be related to the 0401 code. only thing you can do is drive for a little and see if the light goes off.