CEL P0174

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Sep 17, 2008
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I clear it and it comes back. 2002 5.4L F-150 w/44k miles. Cleaned the MAF and checked and tightened all the clamps on all the inlet stuff. I think it says that it means a lean condition on the right bank. Any ideas?
 
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Plugged or dirty injectors is one possibility. I goggled P0174 for Ford and in addition to what you have checked it mentioned the Differential pressure sensor for the EGR system.
 

kaboom10

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Thanx. Injectors are new and fuel system has had cleaner run thru it already. I don't want to throw parts at it but that DPS sensor could be the culprit. I can't seem to find any hose that needs replacement but it's a 7 yr. old vehicle.
 
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On my SIL's 98 Windstar the culprit was a (very) dirty in-line fuel filter. I also cleaned the MAF prior to this and it did not fix the issue. That fuel filter was the original factory filter and the van has around 160k on it. That filter looked like the bottom of a an aquarium that needed serious cleaning! New filter, runs great now, codes cleared and never returned.
 
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The lean code for my 94 5.0 was 172. If you haven't changed it recently, a clogging fuel filter can cause this due to the reduced flow to injectors. A weak fuel pump or bad HEGO sensor can cause this code also.
 
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Lean Bank 2 (driver's side) If that is the only code suspect either a MAF problem, vac leak, or O2 sensor problem. This is when a data tool is most useful. Compare both bank's O2 readings, and fuel trims and crosscounts. If both sides trim lean under load, suspect MAF. If lean at idle, look for a vac leak. If only one side is trending lean while the other is even, suspect an O2. A bad MAF can cause one bank to code as in any system with that many miles will have one O2 sensor a bit lower in voltage, and slower on crosscounts than the other. A fuel pressure or MAF problem effects all cylinders the same, but the weak O2 codes first so people/idiots/shadetrees throw a sensor at it first only to throw another sensor on the other bank a few hundred miles later when that one codes.
 

kaboom10

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Thanx. Never thought to run a data log. I've got the capability so I'll give it a try. Shoulda done that first before even opening the hood. Thanx again.
 

kaboom10

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If I don't find anything from a data logging that's gonna be my first guess on replacements. I should just get a can of throttle body cleaner and pull it off. Most of what few miles the truck has seen is slow speed city. I let it ramp up to 4000 rpm ever so often as a shift point. Oh it's got a 4.88 rear end ratio. Shifting like that and u hit 40 out of 2nd gear.
 
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Any modifications or exhaust work? I installed a new catback and y-pipe on my car and soon after my CEL came on with that code. I told it can pop when a car's adjusting to anything new. The code was cleared 8 months ago and it never came back.
 

kaboom10

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Inlet pipe and air filter have been upgraded along with a muffler replacement. I don't suspect either as it's been a long time ago. The computer has the capability of learning to operate with minor changes. I can turn mine off and on with the PRP program. I leave it on as I want it to learn any changes to the air/fuel and spark tables.
 
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 Originally Posted By: bdcardinal
try the DPFE, its commonly replaced when that code pops up.
I don't think you throw a 9J460 at a lean code.
 
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 Originally Posted By: punisher
 Originally Posted By: bdcardinal
try the DPFE, its commonly replaced when that code pops up.
I don't think you throw a 9J460 at a lean code.
true youre right, tired from watching Le Mans. although i think we have a tech who throws at 9J460's at everything.
 
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Pull the plugs and see if any look like they've been running lean. If any do that fuel injector is probably partially clogged. Double check for any vac leaks on the aftermarket inlet pipe. If all the plugs look ok and all injectors are flowing correclt the you might try swapping the upstream O2 sensors from side to side. Then clear the ECU by disconnection the battery. Drive it for a while and see if the code comes back on the same bank or on the other. If it comes back on the other bank then the O2 sensor is bad.
 
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 Originally Posted By: kaboom10
If that thing is gonna need that much trouble I'll use it for target practice. lol
If you don't want to put much work into it then at least swap banks with the O2 sensors and clear the PCM. That shouldn't take more than 20 minutes. It's very easy to do. Then drive it like normal and see if it throws any more codes. If that's enough work for you to just decided to use it for target practice let me know. I'll bring a trailer up there and take it off your hands.
 
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Ok, If you're physically unable to do it then I understand. Still though, you gotta know someone that would be willing to help you out and swap them.
 
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