00 V70 XC SE What's up with the security screws on the MAF?

[EngineeringBloke]

And the Bosch MAF sensor has a top mounted temperature sensor - the wire that forms a U-shape coming out from the sensor connector side, and the hot film air mass detection plate that is recessed in a duct within the sensor.

When cleaning a MAF sensor be sure to spray inside the duct near the tip of the sensor to clean the internal sensing plate. Do not touch any part of the thumb shaped sensor with fingers or the straw on the MAF cleaner.

The sensor measures the effect of the cooling of the air as it flows over the sensor plate which is heated and maintained at a temperature. The temperature of the air is measured by the other part of the sensor and factored in to increase the air mass based on colder air being more dense.

Bosch has an video showing the two sensors in the MAF. Also the duct in the MAF has a bypass hole to allow any solid or liquid matter to exit and not pass over the hot film plate. This aids in keeping it clean.

https://www.boschautoparts.com/en/auto/ ... ow-sensors

In fact, I am somewhat skeptical that cleaner will even make it to the hot film sensor. Still it is worth ensuring the temperature sensor is not dirty and out of calibration as a result.

[erikv11]

I would also note that anecdotally, cleaning the MAF almost never makes a difference unless it is visibly oily. So I would never do it as a preventive measure. Cleaning the MAF is like putting in an aftermarket one - usually a waste of time and money.