CEL P1131

[bigdog225]

Hello all. Im new to the site as I just yesterday bought my first mustang. 1996 Cobra.

Lots of performace add on's including from what I was told no cat with eliminators. So as im driving it home i get CEL P1131. Did a little research before posting and from what im seeing its O2 related (no cat eliminators not working) or MAF sensor. Gut tells me the O2 issue with Eliminators is the culprit. Anyone else running no cat and what did you do to solve the issue? Car came with Tuner programmer I havent really looked at yet and I also have a CEL reader. From other readings I understand that one of these devices would allow me to just disable the O2 reading part to fix the CEL? Any help-suggestions is appreciated.

[GateJockey81]

You shouldnt get a light with MIL eliminators. Put new O2 sensors in and reset the light. Check for vacuum leaks just to cover your bases.

[VMT]

The Diablo allows you to "turn off"your rear o2 sensors so you wont get a cel when you go w/ an o/r pipe.I installed a set of the BBK mils and turned off my rear o2 sensors after my L/T install,no light.Which hand held do you have?

[hotcobra03]

Hello all. Im new to the site as I just yesterday bought my first mustang. 1996 Cobra.

Lots of performace add on's including from what I was told no cat with eliminators. So as im driving it home i get CEL P1131. Did a little research before posting and from what im seeing its O2 related (no cat eliminators not working) or MAF sensor. Gut tells me the O2 issue with Eliminators is the culprit. Anyone else running no cat and what did you do to solve the issue? Car came with Tuner programmer I havent really looked at yet and I also have a CEL reader. From other readings I understand that one of these devices would allow me to just disable the O2 reading part to fix the CEL? Any help-suggestions is appreciated.

this is a right front o2


mils are used on rears

[hotcobra03]

P1131 - Lack of HO2S-11 Switch, Sensor Indicates Lean A HEGO sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time. See Possible Causes for DTC P1130

P1130 - Lack of HO2S-11 Switch, Fuel Trim at Limit The HEGO Sensor is monitored for switching. The test fails when the HO2S fails to switch due to circuit or fuel at or exceeding a calibrated limit. Electrical:
Short to VPWR in harness or HO2S
Water in harness connector
Open/Shorted HO2S circuit
Corrosion or poor mating terminals and wiring
Damaged HO2S
Damaged PCM
Fuel System:
Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Induction System:
Air leaks after the MAF
Vacuum Leaks
PCV system
Improperly seated engine oil dipstick
EGR System:
Leaking gasket
Stuck EGR valve
Leaking diaphragm or EVR
Base Engine:
Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near the HO2S(s)
A fuel control HO2S PID switching across 0.45 volt from 0.2 to 0.9 volt indicates a normal switching HO2S.

P1131 —
All Others — GO to H40 GO to H40

H40 DTCs P1131, P1132, P1151, P1152, P2195, P2196, P2197 AND P2198: UPSTREAM HO2S NOT SWITCHING.
Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.

DTC/HO2S Reference List:

HO2S-11 = DTCs P1131, P1132, P2195 and P2196
HO2S-21 = DTCs P1151, P1152, P2197 and P2198
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.
Were any concerns found during inspection?
Yes No
REPAIR as necessary. GO to DC25 .

DC25 DTC P0171, P0172, P0174, P0175, P1131, P1132, P1151, P1152, P1130, P1150, P2195, P2196, P2197, P2198 OR LEAN DRIVEABILITY CONCERNS: CHECK CONDITIONS RELATED TO MAF SENSOR
Note: Most weather service reports are a local barometric pressure that has been corrected to sea level. However, the BARO PID reports the actual barometric pressure for the altitude the vehicle is being diagnosed in. Local weather conditions (high or low pressure areas) will change the local barometric pressure by several inches of mercury [+/- 3 Hz. (+/- 1 in.Hg.)].

Verify the MAF sensor is connected. If not, repair as necessary.
Key on, engine running.
Access the BARO, LONGFT1, LONGFT2 and MAF V PIDs on fully warmed-up engine.
Check that the BARO PID is approximately the same as the barometric pressure reading for the location, day and altitude the vehicle is being diagnosed at.
BARO PID values in Keep Alive Memory require updating at high throttle openings. If vehicle is driven down from higher altitudes for diagnosing, complete three or four heavy accelerations at greater than half-throttle to allow BARO PID to update.
BARO PID must be within +/- 6 Hz. (+/- 2 in.Hg.) of the altitude value in Barometric Pressure Reference Chart (at the beginning of this pinpoint test).
Make BARO PID comparisons to Barometric Pressure Reference Chart or daily airport barometric pressure reports, if available.
Check that the LONGFT1 and LONGFT2 PIDS for all injector banks at idle is not more negative than -12%.
Check that the MAF V PID at idle and neutral is not greater than 30% of the normal MAF V listed in Section 6 , Reference Values (or not greater than 1.1 volts).
Are two of the above three checks OK?
Yes No
For DTC P0171, P0172, P0174, P0175, P1131, P1132, P1151, P1152, P1130, P1150, P2195, P2196, P2197 or P2198 : GO to H42 (or GO to HA42 for natural gas vehicles only). For driveability symptoms without DTCs : RETURN to Section 3 , Symptom Charts for further diagnosis. KEY OFF. GO to DC26 .

DC26 CHECK TO ISOLATE MAF SENSOR FROM LEAN DRIVEABILITY OCCURENCE
Note: Due to increasingly stringent emission/OBD II requirements, a fuel system DTC on some vehicles will be generated without a noticeable driveability concern with or without the MAF sensor disconnected. Under these conditions, if the BARO, LONGFT1, LONGFT2 and MAF V PID indicates a MAF sensor concern, replace the MAF sensor.

Disconnect the MAF sensor.
Key on, engine running.
Drive the vehicle.
Is the lean driveability symptom (lack of power, spark knock/detonation, buck/jerk or hesitation/surge on acceleration) gone?
Yes No
REPLACE MAF sensor.

RESET Keep Alive random Access Memory (RAM) (REFER to Section 2, Powertrain Control Module (PCM) Reset ).

VERIFY a symptom no longer exists. For DTC P0171, P0172, P0174, P0175, P1131, P1132, P1151, P1152, P1130, P1150, P2195, P2196, P2197 or P2198 : GO to H42 (or GO to HA42 for natural gas vehicles only).

For lean driveability symptoms listed without DTCs : RETURN to Section 3 , Symptom Charts for further diagnosis

[bigdog225]

The Diablo allows you to "turn off"your rear o2 sensors so you wont get a cel when you go w/ an o/r pipe.I installed a set of the BBK mils and turned off my rear o2 sensors after my L/T install,no light.Which hand held do you have?

SCT SF3

[bigdog225]

this is a right front o2


mils are used on rears

Is this right when looking from under the hood or right from sitting in the car. So basically driver or passenger side? Do I get to it from under the car or under the hood? If you can tell me exactly where to find it that would be great as im not real mechanically inclined but love to try. I appreciate you help. Thanks

[hotcobra03]

Is this right when looking from under the hood or right from sitting in the car. So basically driver or passenger side? Do I get to it from under the car or under the hood? If you can tell me exactly where to find it that would be great as im not real mechanically inclined but love to try. I appreciate you help. Thanks

from drivers seat right front is #11,,,LEFT FRONT IS #21,,,RIGHT REAR IS #12 LEFT REAR IS #22

THERE IS A LINK ON THIS SITE FOR A CHILTONS MANUAL FOR ALL CARS

it will help you for all your question,,,than use this site for help from others