As an Echo of what
@Mooseman has covered for issues that need to be sorted out about any MAF Codes… Paul “Scanner” Danner puts on a Two Part Clinic on “How To Diagnose the GM MAF Sensor and Circuit”.
To Cut to the Chase on the Salient Points:
(1) Of the Three Diagnostic Tools that might be used to look into what the MAF is doing… Right or Wrong:
A High End Scanner
A Decent DMM or DVOM
An Oscilloscope
The ONLY Tool capable of rapidly reading the Higher Signal Frequencies and Drop Outs or Power, Ground and Signal Wire Drop Outs produced by the MAF…
is an Oscilloscope.
(2) Try side stepping any “Exotic Diagnostics” by looking for something PHYSICALLY WRONG First.
You just bought a Stranger’s Truck with fairly High Mileage and have no idea about whether it was driven every day… or left sitting in a parking lot somewhere and attracting 'Rodent Residents' that enjoy Chewing on Wiring Harnesses and Plastic Connectors.
(3) In order to Check Out the MAF Sensor, MAF Sensor Connector and the MAF Sensor Wiring Harnessing for any Breaks or Shorts, Start the Truck and while a “Helper” mashes down on the Gas Pedal to briefly hold it running at around 1,500 to 2,000 RPM… while you:
Gently Press Down on the Outside areas of the MAF Black Plastic Housing.
Slightly attempt to Move the MAF Connector around where it is plugged inside the MAF Sensor.
Perform a MAF Wire Harness “Jiggle” Test.
If the Engine suddenly Stumbles or Dies from any of these actions...look more closely at that Narrow Issue.
(4) Follow the Suggestion made by “Scanner Danner” to use the Point of a Pin Back-Probe and rework the Metal Pin Contacts hidden inside of the Female MAF Connector Ground, Power and Signal Wire locations back to having a better contact surface with each of the Three Internal Male Pins of the MAF.
Don’t get Too Enthusiastic or you’ll Damage the MAF Connector. These images illustrate How he did THIS:
(5) Watch BOTH of these “Scanner Danner” Student Training Sessions for all of the Fine Grain Details and Step-By-Steps involved for a complete understanding of his Diagnostic approach.
Part 1:
Part 2:
(6) CHECK ALL OF THE GROUNDS FOR THE ENGINE BY USING THIS INFORMATION:
While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...
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(7) If you want to know more about getting and using inexpensive Hantek or PICO-Scope Oscilloscopes, visit THIS Thread:
You don't need a Huge Bag of Coins in order to obtain and use an Oscilloscope for performing In-Depth Wave Form Analysis in Automotive Applications on everything from Problematic Electronic Fuel Injection to obtaining accurate Compression Tests to Diagnose Internal Engine Conditions. HANTEK...
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