P1151 code after parts replacement!

[Firefighter6484]

I have an 02 with 4.0L.

I just recently purchased and have completed almost all of the scheduled maint. items dues to it having 180K on it. Vehicle runs great with no noticeable problems.

I just replaced the PCV and IAC valve, along with cleaned the MAF with MAF cleaner and made sure all the connections were tight and everything was in good order. After starting it up I almost immediately got the P1151 code. So I did looked up the code on http://www.obd-codes.com/trouble_codes/ford/p1151.php and rechecked everything.

Everything looked good and I reset the code. The next day it came back on while going to work. I haven't had the chance to check everything again, but will hopefully tonight.

So i am wondering if anyone has anything specific they can tell me to check or maybe i overlooked. Everything seems to be running fine and do not notice any issues other than the MIL.

Thanks

Gary

 

[Firefighter6484]

Also I have put in a K&N Filter about a week before. But the code did not pop up until after I replaced the PCV and IAC and cleaned the MAF.

Could I have screwed up the MAF with cleaner? I hope not. I figured it I screwed it up i would have bigger problems than just a code.


Thank again!

 

[xplorercrazy]

Well to start with the p1151 code pertains to your O2 sensors and not the MAF sensor. However a bad or damaged MAF may cause the code to set due to the computer not knowing how much air is entering the engine exactly thus throwing of the air/fuel mixture. I would first check all of the following to verify that none of them are causing the code to set. If nothing is found then you need to proceed through the diagnostic steps to determine what the source of the problem is.

From the FSM

H40 DTCs P1131, P1132, P1151 AND P1152: UPSTREAM HO2S NOT SWITCHING. DTCs P1130 and P1150: FUEL SYSTEM NOT SWITCHING AT FUEL TRIM (RICH OR LEAN)
Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.

DTC/HO2S Reference List:

HO2S-11 = DTCs P1131, P1132 and P1130
HO2S-21 = DTCs P1151, P1152 and P1150

Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.
Were any concerns found during inspection?

 

[Firefighter6484]

Well I rechecked everything, And did not notice any loose connections or leaks. Not real sure what the best way to detect vaccum leaks would be. I have heard to use baby powder??

But a day later the code came right back. So I think I am going to put the old parts i replaced back on one at a time to see if one of those may be causing the problem.

Anyone have anymore ideas??

Thanks

 

[xplorercrazy]

Well the best way to detect vacuum leaks is with a smoke machine. But since those are expensive and most people don't have access to one the next best thing is to spray carb cleaner around all intake connections and gasket areas. If there is a leak the engine should change rpms when it sucks the cleaner in through the leaking area.

 

[Firefighter6484]

Well a few days ago I went in and re-checked. Used an entire can of carb/choke cleaner looking for vaccum leaks and sprayed some in the intake itself.

put everything back together, and cleared out the code. to date still no code pop back up so I guess it was either dirty or something was just not sealing tightly.

Thanks again for your help