Maf sensor p0102 code

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20
Location
Green Bay, Wisconsin
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Hello, I have recently got an obd2 code of P0102 "mass or volume air flow circuit low input" on my 2002 Buick Lesabre with a 3800 motor and 130k miles on the clock. After the code was set I connected my scanner and monitored and trended the signal while driving and what I noticed was that the sensor appears to be reporting the correct air flow rate but intermittently the signal would flat line for a few miles and then return to operating normally. The car does not idle real smooth and has an intermittent miss also at idle but otherwise seems to run okay with the "fuel trims" normal. I have removed the sensor and inspected it and visually everything looks good, also checked the power and ground wiring with a volt meter at the connector and all checked out okay. So I am looking for any advice as for anything else to check before I throw a new sensor at it. Any thoughts would be greatly appreciated.
 
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1,767
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Toronto Canada
Clean the sensor, this may fix the problem. With the engine running and the scanner hooked up, wiggle the wires at the sensor and all the way to the ECU. Listen for a change in how the engine is running and see if the scanner to flat lines.
 
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4,112
Location
WA
I'm pretty sure the MAF works off resistance of the fine wire(s). So the wire or wires, some MAF can have more than 1, either are working or not. I've never heard of a "resistor" partially working but it's possible the wires could be dirtied up and need cleaning - I do that every couple of years when I clean the TB and MAP sensor. If that doesn't work look at the contacts, connector and wiring. And I'm gonna state the obvious just in case, don't touch the wires with ANYTHING..they break easily and use CRC MAF cleaner only - nothing else. There's some good vdeos on YouTube about diagnosing MAF problems.
 
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4,728
Location
Fort Worth, Texas
Observe the "Grams Per Second" PID while lightly tapping on the sensor with the butt of a screwdriver & watch for signal drop out. The same procedure can be used for wiring/connection issues (Wiggle test).
 
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866
Location
Indy
Great advice above. Only thing I can add is to check for vacuum leaks, as this can make the MAF have a false reading. Or simply an air leak between the MAF and throttle body, suck as a torn or cracked intake boot. This will not usually throw a lean code, since the air leak is post MAF and pre throttle body. Good luck. Hope it doesn't get in your wallet too bad. CRC MAF Cleaner is great stuff.
 
Messages
20
Location
Green Bay, Wisconsin
Thread starter
Thank you all for the advice. I just did the wiggle/ tapping test while monitoring the "g/s" output on the scan tool and saw no changes in the signal. I'm going to pickup some Maf cleaner tomorrow and give it a cleaning and see what happens. Thanks again..
 
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4,728
Location
Fort Worth, Texas
Originally Posted by 69Torino
Great advice above. Only thing I can add is to check for vacuum leaks, as this can make the MAF have a false reading. Or simply an air leak between the MAF and throttle body, suck as a torn or cracked intake boot. This will not usually throw a lean code, since the air leak is post MAF and pre throttle body. Good luck. Hope it doesn't get in your wallet too bad. CRC MAF Cleaner is great stuff.
No boot between the throttle body & MAF on a Buick 3800.
 
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4,728
Location
Fort Worth, Texas
Originally Posted by JohnMack
Thank you all for the advice. I just did the wiggle/ tapping test while monitoring the "g/s" output on the scan tool and saw no changes in the signal. I'm going to pickup some Maf cleaner tomorrow and give it a cleaning and see what happens. Thanks again..
I would break out the Scope at this point & Backprobe the Signal Circuit (Yellow Wire) & observe/datalog the 0-5 volt Square Wave pattern while driving the car. *The Frequency Increases proportionally with Air Flow! If the scan tool data PID drops out but the Square Wave on the Scope doesn't......Suspect the Signal Circuit to the PCM for a intermittent open, Bad Connection at the PCM, Or a Faulty PCM. *To eliminate the Signal Circuit as the problem.....Backprobe at the PCM connector & road test again. *If drop out in Scan Data is still present & the Scope does not.....Suspect a bad connection at the PCM or a Faulty PCM. *You can unpin the Signal Circuit from the PCM Connector & do a "Drag Test" on the PCM Terminal.....There is tool for this but I would suspect you don't have one. If Scan Data PID AND the Scope drop out.....Suspect a faulty MAF, Intermittent loss of Power/Ground. *I will substitute Power & Ground in situations such as this using a Replacement/Test MAF Connector. Pink to Battery Power. Black to good engine ground. Unpin the Signal Circuit (Yellow Wire) & pin it into the Test Connector. *Road test the car again. Intermittent issues can be fun to accurately diagnose & require a process of elimination using the right equipment! Firing the Parts Cannon at it with a new MAF may be the best path for you at this point? Intermittent signal drop out IS NOT indicative of a dirty sensor!! A dirty sensor will Under Report airflow!!
 
Messages
20
Location
Green Bay, Wisconsin
Thread starter
Thank you very much for the detailed information you took the time to post!! As I do not have a scope, testing the signal out if the sensor is not an option. I have backprobed the connector and loaded the power and ground wires with a 2.7 amp load (1157 bulb) while giving things the wiggle test and all looks good to me. I think at this point I might shoot the parts Cannon and replace the sensor and see what happens.
 
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