2008 duramax mass air flow sensor problems

To prevent that, all signal circuits have an internal 'pull-up' or 'pull-down' resistor tied to 5.0 volts or to ground. When the signal voltage is allowed to float, if it happens to stay within that acceptable range, the computer will regard that as a proper voltage, and it will try to run the engine on that. Anything outside that range is what triggers a fault code. For explanation purposes, the acceptable range of signal voltage from a sensor is 0.5 to 4.5 volts. When there is a break in the signal wire circuit, whether it be a cut wire, or corroded terminal, since the wire inside the computer is tied to a lot of other circuitry, the voltage inside the computer on that line can 'float' to some random value. Service manuals always list that as the first thing to look for, especially when there might be a plug that was recently disconnected for something else. That comes from cleaning off excessive corrosion or from stuffing a meter probe in too far that is larger in diameter than the male part of the terminal. I will explain later what I am after when I am done fighting with this miserable computer! That is going to be either 0.2 volts or 5.0 volts. Unplug the MAF sensor, turn the ignition switch on, then read the voltage on the signal wire. There is something else you can do to help me help you. If your engine uses a MAP sensor too, it may be running in back-up mode off that sensor. That will cause the signal voltage to be always below the threshold at which it sets code 102.

The first thing I would suspect on yours is the power supply terminal is stretched in the connector body. These also do not have a record function which is useful when watching for intermittent problems on a test-drive. Rapidly-occurring glitches and changes will be missed. Be aware that those I have tried do provide sensor data, but the screens only have three or four lines of data, and they take as much as five seconds to update.

You can also find some inexpensive models on eBay that will do what you need for under $100.00. You might find one at an auto parts store that rents or borrows tools. Professionals use scanners that cost between about $1000.00 and $3,000.00. I know it can be a problem knowing if the meter's probe made contact with the terminal when you back-probe through the weather-pack seal, but if you get any voltage reading other than 0.0, you know you are in there.

2008 duramax mass air flow sensor problems