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Discussion Starter #1
Background: Was getting Code P1131 So I did a search found some info on the possible causes..


Ok so I cleaned my MAF using some electrical cleaner and a Q-tip. I was extra careful and did not break the wires, made sure by using a magnifying glass.

Plugged it back in and no change in the way the car was running before. I did however notice that it seemed to run slightly worse with the MAF plugged in.

Im not sure if it made a difference plugged in or not before I cleaned it because the car wasnt running.


What should I look into now? New MAF?



Thanks in advance.



FantasticVoyage
 

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H40 DTCS P1131, P1151, P1132 AND P1152: UPSTREAM HO2S(S) NOT SWITCHING. DTCS P1130 AND P1150: HO2S NOT SWITCHING, FUEL SYSTEM AT THE ADAPTIVE LIMITS (RICH OR LEAN) P0172, P0174, P0171 AND P0175: FUEL SYSTEM AT ADAPTIVE LIMITS

NOTE:
Before servicing DTCs P0171, P0172, P0174 and P0175, verify with the customer that before the "Check Engine Light" came on, the vehicle did not run out of fuel.

Diagnostic Trouble Codes (DTCs) P1131 and P1151 indicate the system is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt.

DTCs P1132 and P1152 indicate the system is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.

DTCs P1130 and P1150 indicate the fuel control system has reached its maximum compensation for a lean or rich condition and HO2S is not switching.

DTC P0171, left bank, and DTC P0174, right bank, indicate the fuel/air ratio is too lean. The system is at the rich limit.

DTC P0172, left bank, and DTC P0175, right bank, indicate the fuel/air ratio is too rich. The system is at the lean limit.

DTC/HO2S Reference List

-- HO2S-11 = DTCs P1130, P1131, P1132, P0171 and P0172

-- HO2S-21 = DTCs P1150, P1151, P1152, P0174 and P0175

Possible causes:

Fuel System

-- Excessive fuel pressure.

-- Leaking fuel injector(s).

-- Leaking fuel pressure regulator.

-- Low fuel pressure.

-- Plugged injector(s).

-- Damaged/disconnected HO2S circuit.

Induction System

-- Air leaks after MAF.

-- Vacuum leaks.

-- Restricted air inlet.

-- PCV system.

Base Engine

-- Oil overfill.

-- Cam timing.

-- Compression.

Ignition

-- Coil and secondary side of ignition system.

l Check air intake for leaks, obstructions, and damage.

l Check air filter, air filter housing for blockage.

l Check positive crankcase ventilation system integrity.

l Check engine vacuum integrity.

l Are there any obvious concerns?

Yes
REPAIR any of the problems found in the visual inspection. RERUN «Quick Test».

No
GO to «H41».
 

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Make sure there's no Q-tip fibers left on the MAF sensor wires. Perform the computer reset: remove fuse #15 from the Power Distribution Box in the engine compartment (near the battery), start the car (it won't start), replace the fuse, and go out for a good, middle-speed drive (~a steady 50mph is what I usually do).

If no improvement is observed, start checking the items Rolling-Thunder posted. It could be that an oxygen sensor is failing. The pinpoint test is rather lengthy for posting. Read it here (it's an MS-Word document), and you'll see what I mean.
 

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Discussion Starter #4
thanks guys that was super fast response :) I made sure the maf was spotless before I put it back in. I will reset the computer this afternoon and hope that fixes it if not Ill start the long process.



Thanks again

FV
 
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