996TT Down on Power and Only Reading .4-.5Bar???

So you might be googling this and wondering why your ABS/PSM light is on and your Porsche 996 Turbo is only making .4 or .5bar.  Don’t blame the tune, don’t yell at your dealer.  This is a common problem for the Porsche 996TT cars with higher mileage or aftermarket intakes.  What happens is the MAF sensor goes bad putting the car into limp mode.  The MAF is located on the left side of the engine bay just behind the intake box on the intake tube.  It requires a special T6 tool from Porsche to remove the bolts.  This part can be replaced from anywhere around $200-$400 depending on the supplier.  MAF can go bad for a number of reasons.  Usually what will cause a bad MAF is unlaminar airflow.

The factory intake has a waffle looking screen that goes betwen the MAF and the intake box filter.  This keeps the airflow that goes past the MAF laminar or “straight”.   Turbulence can cause that very sensitive MAF sensor to fail.  Another cause of the MAF failure is over oiling your aftermarket filter or touching the sensor and getting “dirt” on it.  Make sure to only handle the sensor by the top plug and never grab the sensor part.

The 996TT MAF controls many applications in the car, when tuned properly, these can handle up to 800 horsepower at the crank.  Remember to always run a diagnostic check on your car to see what codes may come up.