TEST MAF SENSOR UNPLUGGED SOFTWARE

If this test fails there could be an airflow issue but MAF sensors could still pass this test and be faulty. This is exactly two times the engine displacement. When the engine returned to idle the MAF reading is 4.00 grams per second. In the following example (Figure 1) I snapped the throttle a few times on a 2.0 liter naturally aspirated Ford product. The way it works is: at idle the engine should draw approximately two times the engine displacement in grams per second. It will alert you to a gross MAF failure but nothing more. The double the displacement rule is a mediocre test. I am putting my foot down… this test is basically worthless. Some modern vehicles will not even run with the MAF sensor disconnected.

TEST MAF SENSOR UNPLUGGED SOFTWARE

Modern vehicles have software strategies that render this technique useless. If we were working on a 1986 Pontiac 6000 that may have been acceptable. I have been in this industry for many years and I can say that unplugging a MAF sensor used to be a good tactic. Regardless, there are multiple ways to test MAF sensors and I will do my best to go through them all. In other cases, a failed MAF sensor will cause lean codes such as P0171 or P0174. In addition, mass air flow sensor issues usually present themselves as a drivability problem with no DTC or MIL illumination. During diagnosis mass air flow sensor codes are usually an indication of another underlying problem. MAF sensors are one of the most common “Shotgun” parts that technicians swap. It can affect fuel delivery, transmission shifting and more. Air flow measurement is a HUGE input on Mass Airflow sensor (MAF) equipped vehicles. If you did not know, the engine has to be operating properly before we can diagnose transmission problems.

Test maf sensor unplugged