DTC Code P1131

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falcn

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Tonight when driving home from work my 1997 Expy Eddie Bauer with 5.4L check engine light came on.

I noticed no change in performance - no shuddering, hesitation, etc.

I went to Autozone and borrowed the code reader and the code pulled was P1131.

Where would you start on the list below?

Or should I just replace the HO2S-11 Oxygen sensor?


We just got the vehicle on Dec. 1st - 73K miles on it now.

This link shows:
http://v8sho.com/SHO/TSB0197HO2SServiceTips.htm

"P1131 - Lack of HO2S-11 Switch, Indicates Lean

When an HO2S sensor indicates lean at the end of a test, the system is trying to correct for an over-lean condition. The code is set when the fuel control system no longer detects switching for a calibrated amount of time.

See Possible Causes for DTC P1130"

Possible Causes:

Electrical:
· Short to VPWR or VREF in harness or HO2S
· HO2S circuit shorted to Ground
· Water in harness connector
· Open circuit
· Corrosion or poor mating terminals and wiring
· Damaged HO2S
· Damaged PCM (other DTCs should be present)
Fuel System:
· Excessive fuel pressure (stuck fuel pressure regulator, restricted fuel return lines, etc.)
· Leaking/contaminated fuel injectors or fuel pressure regulator
· Low fuel pressure or running out of fuel (fuel pump concern, fuel supply line restrictions, low fuel level, etc.)
· Vapor recovery system (stuck VMV, etc.)
Induction System:
· MAF contamination
· Air leaks between MAF and throttle plate
· PCV system / Other vacuum leaks
· Improperly seated engine oil dipstick
EGR System:
· Leaking gasket
· Stuck EGR valve / Leaking diaphragm or EVR
Base Engine:
· Oil overfill
· Incorrect cylinder compression
· Exhaust leaks before or near the HO2S
· Secondary air stuck on
 
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JUST4FUN

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i would replace fuel filter first and go from there
 
OP
OP
F

falcn

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I cleaned the MAF sensor wires - cleared the codes - no more CEL - and it is running better and gets better mileage.
 

tarafied1

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I know this is an old topic but I thought it would be good for those who are serching.
I have had lots of codes recently on my 2000 EB with the 5.4 V8.
I changed the DPFE sensor for insufficient flow at the EGR. It didn't help. I pulled the throttle body and intake and cleaned it, changed EGR and then got the p1131 code. I cleaned the MAF with some spray and have had no more issues.
 

monicacorzo

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Expedition 03

I have the same trouble with my expedition, I replaced the fuel pump and filter also the fuse box because the fuel pump relay inside wasn't working, runs better but still make like a little jump. Then I replace the spark plugs, coil boots they had rust and looks like tartar was building in... runs better but still does a little jump it feels less than before but I don't know what else to check still getting the same code P1131
 
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