OBD II Mass Airflow Code Tech Tip

In this tech tip we will show you the FIRST thing to do on a MAF sensor code.

The test car is a 3/97 S70 2.4L turbo Volvo with only 41k on the clock.

Symptoms: Tip-in hesitation, Surge, Rolling idle, and best of all, the famous Yellow Light.

Ø Attach the units power leads to the battery. Red to (+) and Black to Chassis Ground.

Ø Attach the supply hose to a direct vacuum manifold source.

Ø Insert the proper yellow cap plug into the

air induction inlet hose. Place the cap between

mass airflow sensor and the air induction hose

shown in the picture. Remember it is important

to block the intake so it can build pressure.

Ø Push and hold remote control button.

Don’t forget that leaks can be found in areas

that you least expect. Take the time to look.

Ø Get any bright white light (spot or mag)

Ø At this point, shine the (spot or mag) light, in the area described below.

Drivers side rear of engine, down by the turbo,

under the waist gate actuator, where it is almost

impossible to see or to get to. You may find a

number of leaks but any one can cause the problem.

You can see a small puff of smoke in the picture

to the right (red arrow). This leak is big enough to

cause that all famous yellow light to come on.

There is no Scan tool, Gas or Engine Analyzer, Lab Scope, or Voltmeter on the planet that can pinpoint this leak like this unit can. (In 3 minutes or less).

The story here is, before you break out your arsenal of equipment, that we all know can’t pinpoint the leak, take the 3min. to test it with diagnostic smoke to find the leak(s) and repair.

Now, what will YOU do first?