99 Explorer throwing codes (Newbie, HELP)

[Jaimec]

I'm new here, but I'll try to keep it short.

I've been looking at buying an Explorer for over 2 years, and have done my due diligence, to the best of my ability. I have been lurking on several forums, as well as googling potential problems for various years, as well as the repairs involved.

So, here's the deal.

I found a 99 Explorer (supposedly an XLT, but the body doesn't say that, and the trim package doesn't support the claim, other than alloy wheels....have yet to see the title, so I don't know). The price was great, HOWEVER, it was throwing a couple of codes.....P0171, and PO174. Both banks too lean. My first thought was MAF.

Took it back to the dealer and they were miffed. Turned out the Check Engine Light wasn't working, either The mechanic thought it was the MAF, as well, and cleaned it (I've learned that this doesn't always work). So................I spent 6 hours at the dealership, driving, stopping, and then re-checking the OBDII readings, to see if all sensors had reset. All the while, the salesman assured me that they would get it through emissions, which is the biggest issue for me. I have no reason to distrust the guy, other than he's a used car salesman, which is EVERY reason to distrust him.

So...the results:

1-Initially, I was getting P0171 and P0174 readings.
2-Later that night, after 6 drive cycles, it was still trying to read the codes, with the 'C' flashing and a yellow light.
3-Tonight, it throws the same P0171/P0174 codes, but the 'C' code is solid, and not flashing.

Soooo.....that tells my uneducated mind that.... there was a prior issue with it throwing P0171/P0174 (too lean on both banks), so when reset, it threw no codes until everything had reset itself. BUT....that was when the 'C' code (catalyst) came about. So, once again, I think it has to be related to the catalytic convertor(s), or their sensors, right???? Or O/2 sensors??? Crap, I don't know.

I really like this rig, and want to keep it, but can't afford a lengthy stretch of expensive repairs. Any help would be GREATLY appreciated!


Jaime

 

[jremington59]

What state are you in? In most states it's against the law to inspect a vehicle that doesn't have a working CEL. How are you driving it without an inspection? Is this a 6 or 8 cylinder?

 

[Vic_Ferrari2002]

Welcome Aboard!!!

First of all if its a 4 door then its most likely the XLT their claiming it to be. Only the 2 door were Sports. As far as all the other options the XLT package adds, I have no idea. I am sure someone else can chime in on that. On to the second issue. If your getting both P0171 and P0174 codes my first thought is gonna be leaking lower intake manifold gaskets. I am guessing that your Explorer has either the 4.0 OHV or SOHC motor in it. In those motors the lower intake manifold gaskets seem to be a pretty common issue after so many thousand miles. i would have your dealer start there and see what they find. You could always go ahead and spray some carb cleaner around the intake, if the idle changes while doing that you found your problem. That's what I would suspect, maybe someone else has another idea.

 

[Jaimec]

What state are you in? In most states it's against the law to inspect a vehicle that doesn't have a working CEL. How are you driving it without an inspection? Is this a 6 or 8 cylinder?

Sorry, it's the 6 cyl, and sohc, as far as I can tell. I'm in Idaho.

 

[jremington59]

You should google your states inspection laws. I'm sure the CEL has to be operational. Used car dealers will try anything, lol.

Vics probably correct with the diagnosis if the MAF has been ruled out. Although cleaning isn't always the fix as sometimes they need replaced.

 

[Bobmbx]

Check your DPFE. And while you're doing that, pull the hoses off the DPFE and ensure they are not clogged with soot. Ford DPFE modules have an issue with retaining moisture and either rusting on the inside. Then check the EGR system for clogs.

My 99 Mounty DPFE hoses were choked solid from end to end with soot, and the DPFE was long lost to rust on the inside.

 

[jremington59]

There are only 2 counties in Idaho that require an emissions test. And it's mandatory that the CEL illuminates. If you turn your key to the on position it will illuminate if it's working.

 

[koda2000]

you did your due diligence and still bought a 14 year old SOHC V6? sorry, but this engine has it's problems. beside the 2 codes your seeing, which are usually intake manifold gasket/O-ring leaks, timing chains are a big problem with this engine. are the chains quiet right now (at cold start and while warm)? if not, do everything in your power to get your money back! it should be illegal for a dealer to sell a vehicle with a non-working CEL. I hope you didn't pay too much. how many miles are on it?

 

[jremington59]

you did your due diligence and still bought a 14 year old SOHC V6? sorry, but this engine has it's problems. beside the 2 codes your seeing, which are usually intake manifold gasket/O-ring leaks, timing chains are a big problem with this engine. are the chains quiet right now (at cold start and while warm)? if not, do everything in your power to get your money back! it should be illegal for a dealer to sell a vehicle with a non-working CEL. I hope you didn't pay too much. how many miles are on it?

I'm guessing it's probably not illegal, but is more than sufficient for a refund if the issue and the codes weren't told to him prior to purchase. It wouldn't surprise me if the dealer removed the bulb, lol. In NY they don't play games. If you contact the DMV with proof of a serious infraction they give the dealer only a short period before suspending their license. In NY, when doing an inspection the first question asked the inspector by the program is if the CEL illuminates in the key on position. If he's honest and answers no, it's an automatic fail. He could lie and answer yes, but if caught his inspection license would be immediately suspended pending a hearing.

 

[jimbalaya]

i have a 97 xlt sohc and a few months ago had the CEL light come on with P0171 & P0174 codes. long story short - it turned out to be the fuel filter. see long story below.

Here is the long story: stealership diagnosed the vapor purge valve due to hole caused by leaking battery acid [causing vacuum leak]. They also suggested a bunch of other maintenance/repairs for tons of $$ - I told them very funny, I'll come get the car. I replaced the vapor purge valve myself and confirmed the hole burned into it [almost size of a dime]. thought that vacuum leak fix would do the trick. the two codes returned soon after some around town driving. then removed the MAF and cleaned it - same codes returned. replaced the air intake hose as it appeared to be OE and thought maybe wasn't fitting tight anymore or cracked. no avail. replaced to IAC valve because idle was a little rough [although not related to lean banks codes per se]. same codes. replaced spark plugs because that was way overdue. no difference re CEL/codes. I am at wits end so have mechanic [not stealership] perform a smoke test [looking for vacuum leak]. mechanic says smoke test ok but recommends changing fuel filter, after popping it out and blowing through it and finding it partially clogged. been over month now with various city and hwy driving and CEL light has stayed off.

 

[Jaimec]

i have a 97 xlt sohc and a few months ago had the CEL light come on with P0171 & P0174 codes. long story short - it turned out to be the fuel filter. see long story below.

Here is the long story: stealership diagnosed the vapor purge valve due to hole caused by leaking battery acid [causing vacuum leak]. They also suggested a bunch of other maintenance/repairs for tons of $$ - I told them very funny, I'll come get the car. I replaced the vapor purge valve myself and confirmed the hole burned into it [almost size of a dime]. thought that vacuum leak fix would do the trick. the two codes returned soon after some around town driving. then removed the MAF and cleaned it - same codes returned. replaced the air intake hose as it appeared to be OE and thought maybe wasn't fitting tight anymore or cracked. no avail. replaced to IAC valve because idle was a little rough [although not related to lean banks codes per se]. same codes. replaced spark plugs because that was way overdue. no difference re CEL/codes. I am at wits end so have mechanic [not stealership] perform a smoke test [looking for vacuum leak]. mechanic says smoke test ok but recommends changing fuel filter, after popping it out and blowing through it and finding it partially clogged. been over month now with various city and hwy driving and CEL light has stayed off.

Turns out that it was the #2 sensor on the right bank. Dealer fixed for free, but we couldn't clear the P1000 code, no matter what we tried. The salesman and I drove it for HOURS, and I drove it all weekend, but no go. I personally put $60.00 in gas trying to clear that damned code. Nothing worked. It was looking like I'd be giving the rig back, and looking for another. In fact, the dealer and his mechanic were talking about finding me one (awesome service from these guys!), but I didn't want another one. I wanted this one. They told me to fill the tank and drive it home (40 miles) in a last ditch effort to reset the damned P1000 code. I kept it at the same speed for 21 minutes on the drive, and...........nothing. Still not reset. Out of absolute desperation, I took it to the emissions testing facility. I explained that I was trying to buy the truck, but was certain it wouldn't pass emissions. Well.....IT PASSED!!!!! Well, sort of. The CEL needs to be working (I think it's the bulb, but we'll see), but other than that, it passed inspection.

So.........in this arduous adventure, I got to take it home and drive it for four days without making a commitment (I made them put it in writing that it would pass emissions), so I got a really good feel for the truck. Also, I got to see it up on the rack today, and it has all new ball joints, front end bushings, and new front brakes.

All for the princely sum of $2787.00. Not bad for a rig with 144,000 miles, and the body and interior are good, as well.


Thanks for all the help, guys! I'm sure I will be a regular here from now on!

PS-I have to say that the dealership I dealt with has been absolutely phenomenal through all of this, and I never would have believed that. Kim's Kars in Caldwell Idaho.


Thanks again,
Jaime

 

[jremington59]

Oh, man. Where to start. So they passed it with a sticker with no working CEL? And I can see the sensor causing the code on the pass bank, but what would a pass side O2 sensor have to do with a left bank lean condition?

Do yourself a favor. Do you have anyone local like an AutoZone that reads codes for free? If so, go and have them read the codes that are listed and then let us know.

 

[Jaimec]

Oh, man. Where to start. So they passed it with a sticker with no working CEL? And I can see the sensor causing the code on the pass bank, but what would a pass side O2 sensor have to do with a left bank lean condition?

Do yourself a favor. Do you have anyone local like an AutoZone that reads codes for free? If so, go and have them read the codes that are listed and then let us know.

I guess I didn't explain that very well. No, I didn't get a pass on my emissions, as the CEL was not working (fixed that today....burned bulb). After clearing the codes, and doing a proper drive cycle, it was no longer throwing codes (Lean on both banks), but the E/V wasn't resetting, no matter what we did. Drove the living crap out of it for 4 days. Stop/go, highway, everything. The dealer then tested every sensor, and one was not reporting back. It wasn't throwing a code either, but they replaced it anyway. Still, the E/V wouldn't reset. Out of desperation, I took it for emissions testing, and told them the CEL was out, but wanted to see what their system showed. He told me that the E/V not resetting was a non-issue, and that other than the CEL not working, it was a pass.