1999 Ford Explorer error codes

Tiny
LALFAN1960
  • MEMBER
  • 1999 FORD EXPLORER
  • 4.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 149,000 MILES
I have a 99 explorer that I put plugs and wires on. Had an issue on start up with a tube going into air intake tube that was off and didnt realize it. Got some codes in it for running lean. Found the tube and hooked it up and it ran pretty good. A little rough on start up. Cleared the codes and now I got codes p1157, 1137, 1000, 1151 that came back up. Not sure if I have another leak or why these codes came up again. Didnt have codes prior to doing the plugs. I have looked up some and its 02 sensor not switching or is slow. I have a genisys evo to use for codes. Thanks
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Saturday, March 7th, 2015 AT 10:52 AM

41 Replies

Tiny
ASEMASTER6371
  • EXPERT
On your scan tool, what are the long term trims?

Roy
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Saturday, March 7th, 2015 AT 11:49 AM
Tiny
LALFAN1960
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Long term ft bank 1 22.0% bank 2 21.0% at idle on the datastream
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Saturday, March 7th, 2015 AT 11:54 AM
Tiny
ASEMASTER6371
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Ok, there lies the issue.

I am sure you should have or will show 171,174 codes soon. These come from many possibilities.
Vacuum leak in the intake system
pcv valve bad, stuck open
mass air flow failed. Cleaning has little or no effect.
Low fuel pressure

the codes for the O2 sensors may be coming from the fact that they cannot control the fuel/air ratio with the trims so far out

Roy
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Saturday, March 7th, 2015 AT 12:03 PM
Tiny
LALFAN1960
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OK. I had clear codes and tried driving about 10 miles and no codes yet. What should it be running and the rear 02 sensors don't switch unless u give it dome ROMs or is that normal. Thanks
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Saturday, March 7th, 2015 AT 12:11 PM
Tiny
ASEMASTER6371
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Ok, clearing codes does nothing. That is only done after the issue is found, repaired and the very last thing is to clear them. There is freeze frame info you erased that could have helped us here in determining the failure.

The lean codes will not re appear for a while possibly a day or so.

The rear O2 should be relatively constant. The only job rear O2 sensors have is to moinitor the cat converter. They will not effect the running of the car.

Roy
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Saturday, March 7th, 2015 AT 12:14 PM
Tiny
LALFAN1960
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The codes before just came up on a test drive from an alighnment job. So figure in that much time they would have been back
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Saturday, March 7th, 2015 AT 12:17 PM
Tiny
ASEMASTER6371
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You will have to wait and see. Once they come back, do not clear anything. Use your scan tool and look at the freeze frame data.

Roy
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Saturday, March 7th, 2015 AT 12:19 PM
Tiny
LALFAN1960
  • MEMBER
Ok iwill try to find that if it comes back on. What will I need to be looking for?And far as the maf what kind of test is there for that if I can do it. Thanks
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Saturday, March 7th, 2015 AT 12:26 PM
Tiny
ASEMASTER6371
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Right now, lets look for the codes. The freeze frame ill give the reading at the time the code set. Check the other items firat including the fuel pressure

Roy
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Saturday, March 7th, 2015 AT 12:29 PM
Tiny
LALFAN1960
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Trying get PVC out. So what about the Maf what do I need to do with it to check it?
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Saturday, March 7th, 2015 AT 12:34 PM
Tiny
ASEMASTER6371
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Ok, what is the fuel pressure?

Look for the voltage on the mass air flow at idle. When you rev the motor, it should change according to load.

Did you do the other test as I suggested?
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Saturday, March 7th, 2015 AT 12:50 PM
Tiny
LALFAN1960
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Will have to rent a tester for fuel n figure that one out. Guessing they have a port on top for that. Going to put in new pcv. Was looking at Mac to see if it was dirty. What psi should fuel be
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Saturday, March 7th, 2015 AT 12:59 PM
Tiny
LALFAN1960
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Maf volts at idle.61 and rev it went to 1.94
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Saturday, March 7th, 2015 AT 1:06 PM
Tiny
LALFAN1960
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Light is back on. Codes p0171. 0174. 1000
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Saturday, March 7th, 2015 AT 1:09 PM
Tiny
ASEMASTER6371
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Sounds like mass air flow is working at this point but the freeze frame will confirm.

Yes there is a port. It should be around 45 lbs

you dont need to replace the pcv unless it is stuck open. Check it first before replacing it.

Vacuum leaks are real common issues with these motors. Intake gaskets are common failures.

Roy
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Saturday, March 7th, 2015 AT 1:10 PM
Tiny
LALFAN1960
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OK when I'm on data stream I can freeze it. Is that what u want. And what am I trying to look for
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Saturday, March 7th, 2015 AT 1:15 PM
Tiny
ASEMASTER6371
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No, when a code is set by the computer, the pcm takes a snap shot of all the readings and saves them to a file. That will not happen until a code has been set

Roy
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Saturday, March 7th, 2015 AT 1:17 PM
Tiny
LALFAN1960
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OK. I have 3 codes with the light on. So what do I need to try. Sorry I'm an old car guy. Went to school in 79-80
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Saturday, March 7th, 2015 AT 1:28 PM
Tiny
ASEMASTER6371
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Ok, look for freeze frame data in the codes menu. I need that info

what codes?

Roy
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Saturday, March 7th, 2015 AT 1:32 PM
Tiny
LALFAN1960
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Guess I sent them n didn't go thru or something. P0171. 0174. 1000. I hope I can find the info u want. Not real hood on the scanner yet
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Saturday, March 7th, 2015 AT 1:37 PM

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