chackett

Hi All,

My '02 F15 with 4.2l V6 has about 193k miles on it now and has been a great truck. I'm really hoping to get a bunch more out of her. My check engine light has been on for a while now, so I pulled the codes, and this is what I found:

P1151
P1131
P0171
P0174

The 0171 and 0174 I have seen before, and I'v read some threads suggesting to check the pcv elbow or generall check for vacuum leaks. I've made a weak attempt to check for leaks, but I think based on the number of miles I might as well go ahead and replace the elbow.

I've looked around for some help in terms of pictures or videos to assist with replacing the recommended vacuum components. Is this video applicable?


I also suspect I have developed a rear main seal leak. There is a small oil leak where the oil initially appears to be coming from between the transmission housing and the engine.

So I guess my specific questions are first .. can you help me or point me in the right direction to find the vacuum components I need to replace? What parts, and are there recommended suppliers (other than my local dealer) you recommend?

And what do I make of the P1151 and P1131 codes. I'm not familiar with what it means. I've read the bit about heated 02, but I'm not sure what that's an indication of or what a recommended approach to diagnose and repair for that.

Generally, what else would you recommend I do for preventative maintenance on this truck?

Thanks yall,
Chris

03f15012

I have/had the 1151 code on my 2003 4.2. I'd like to tell you what I have done with mine, but I can't. I can't because its been sporadic, and hasn't come on in about 3-4 months. I've noticed that it came on around cooler to cold days, and has been very warm as of late (upper 80's to lower 90's). Maybe it affects it, maybe not. I haven't had any trouble with it affecting the way it runs or drives. Here is a link about the code. Causes, and possible fixes. The 1131 code is the same, except bank 1.

http://www.obd-codes.com/p1151-ford

Parts-wise, you could could what you need of eBay, or at a parts store. I also had to get my RMS replaced for the same reason. I had a friend do it for $300, parts and labor.

Preemptive maintenance? Just normal servicing. Keep the oil and filter changed, check the trans fluid and drop the pan, and you'll be fine. I'm at 173,900 on mine, and have had no other major problems with it besides the RMS. Its the classic "Take care of it, and it'll take care of you."

chackett

You know ..I've also noticed that it seems to throw these codes during the colder months. I'm in Atlanta, and during the summer it'll be fine .. then sometime over the winter it starts all over again.

I just hope I can find some good threads documenting the replacement of the common offending vacuum elbow. That seems like a good place for me to start on this.

Chris

03f15012

Agreed. It was strange for how often I was getting it around Nov. - Feb. Now I don't get it at all. For now, anyway.

Frank_Ford

before you start spending a lot of money, try cleaning your mass air flow sensor. This is located to the left of your air cleaner and to clean it, buy a can of MAF cleaner from your local autozone or other parts dealer, spray it down, and wipe it off with a clean rag. If the air cleaner is dirty, replace it. Also, change out your PCV valve along with the elbow and hose to the PCV if they are damaged. All of this will cost you less than $50 and take very little time or effort to complete. It may also fix most if not all of your problems. If you are not noticing any problems with your motor performance, most likely you are not getting the proper air / fuel flow thus setting off the codes. A serious vacuum leak will cause your engine to run bad so if it is not running bad, don't fix it. Vacuum leaks can come from vacuum lines and also leaks in the intake manifold which are harder to fix.

chackett

Thanks Frank_Ford I appreciate the reply.

I'm in agreement with you that I'd like to do all the easy stuff first. Even if that's not really my ultimate problem, I'll chalk it up to preventative maintenance. Is the video I posted above a good example of the PCV valve and elbow that I need to replace?

About 5 years ago when I saw my first P0175 or P0174 codes, I took it to the dealer. They said it was the intake manifold gasket, and I think they wanted like close to $1k for the repair. I about had a stroke and googled it. I bought a can of CRC electrical component cleaner and cleaned the MAF. Light went off and stayed off for about 2 years.

Now that you mention it, I do think that sometimes the idle is rough. Especially after the engine has warmed up. I drive about 30 miles home from work each day, and sometimes when I have to stop at the store on the way home .. after I come back from being in the store and start the engine up, it will idle rough. Makes me think maybe the intake manifold gasket might actually be the trouble.

Anyway, I'll start by cleaning the MAF, air filter and looking for more details on how to replace the PCV valve, elbow and any associated hoses. Are there any threads detailing that procedure here?

Thanks again!
Chris

OTG02

I too had those codes at one time. I did find a vac leak fixed it cleaned all I could and put new air filter in code went away for a day then came back. Also took it to ford they told me same as u and bout 750 to fix. We'll let it ride for over a yr and then broke down and tore it apart and replace the isolator bolts and gasket and wouldn't ya know it code went off and no cel since. It's been over two yrs now. I also have the 4.2. Plus the same oil leak as you.

I just replaced both head gaskets and lower intake bout 3-4 weeks ago so had to replace all the bolts and gasket again lol. Blew both head gaskets. Just a good thing I can so my own mechanical work. Or I'd be paying an arm and leg for labor. Parts alone for bolts and gasket cost me bout 120. But for last time with heads and all I've got 1200 in it now.

Hope all works out without having to replace the isolator bots and gasket. It's not all that hard just the back 3 bolts that hold the too intake on are a PITA to get at.

Frank_Ford

[QUOTE=chackett;3562311]Thanks Frank_Ford I appreciate the reply.

I'm in agreement with you that I'd like to do all the easy stuff first. Even if that's not really my ultimate problem, I'll chalk it up to preventative maintenance. Is the video I posted above a good example of the PCV valve and elbow that I need to replace?

About 5 years ago when I saw my first P0175 or P0174 codes, I took it to the dealer. They said it was the intake manifold gasket, and I think they wanted like close to $1k for the repair. I about had a stroke and googled it. I bought a can of CRC electrical component cleaner and cleaned the MAF. Light went off and stayed off for about 2 years.

Now that you mention it, I do think that sometimes the idle is rough. Especially after the engine has warmed up. I drive about 30 miles home from work each day, and sometimes when I have to stop at the store on the way home .. after I come back from being in the store and start the engine up, it will idle rough. Makes me think maybe the intake manifold gasket might actually be the trouble.

Anyway, I'll start by cleaning the MAF, air filter and looking for more details on how to replace the PCV valve, elbow and any associated hoses. Are there any threads detailing that procedure here?

The video seems to make it more complex than it actually is and it does not show a lot of detail. The PCV valve plugs into your valve cover and to remove it you simply pull it out. Then disconnect it from the vacuum hose by pulling it from the hose. If the hose is not damaged and does not seem to be collapsing or leaking, you dont have to replace it. Often the rubber grommet that the PCV plugs into in the valve cover deteriorates and should be replaced. Often, PCV valves will come with a new grommet. You can also buy it from your Ford dealer or go to FordParts.com and buy it on line for around $10. Just replacing the PCV valve will make your truck run better and they are dirt cheap (like around $5) This is often an overlooked maintenance item but very important because if vents gases that build up in your engine and can cause excessive oil consumption and generally running bad engine. On all the vacuum lines, Inspect, Inspect, and Inspect and replace them if they are falling apart, cracked, or collapsed.

You might also try adding a bottle of fuel system cleaner to your next tank of gasoline. This also is cheap and partially clogged injectors could be adding to your problem

If you go out to ebay and search "PCV valve for ford F150" you will find PCV valves, the elbows, and the grommets.

Jbrew

P1131 Lack Of HO2S11 Switch - Sensor Indicates Lean
P1151 Lack Of HO2S21 Switch - Sensor Indicates Lean

In this case, sensor 1 @ both banks are bad.

Yea, make sure the PCV elbow is intact, that would compound the problem, but you need O2's..definitely.

OTG02

Not necessarily need new O2s. I had same prob. Replaced isolator bolts and upper plenum gasket and codes went away. I had same codes he had. Once fixed no codes at all and never replaced my O2s Cleaned everything like everyone is suggesting. And more. Of course I had 5 of 6 egr ports clogged shut too. Lol.