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cls5504matic
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May 2, 2025
- Join DateJul 2019
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i believe it is a map sensor and not all intakes get rid of them.
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As others have stated they are not MAP sensors. They are air quality sensors. The air filter box is not the source of manifold vacuum just air inlet flow. The actual real MAP sensors are mounted onto the charge intercoolers reading actual boost pressure and manifold vacuum. They are located after the throttle body assemblies on both intercoolers where the true source of manifold vacuum is.
I'm going to try and throw some logic at this debate... Here what I think:
I have to agree that they are a pressure sensor. Several people keep saying "air quality" sensor, but what does that mean? ... There is no sensor in the engine that tells you to get out of downtown because the air isn't as "high quality" as in the countryside. That sensor is only available in a Jaaaaag 😂.
Air flow through the airbox causes a change in air pressure inside the box (a vacuum). A clogged air filter would obviously flow less air and therefore have a different pressure reading than a clean air filter..... So even if you call them an "air quality" sensor they are, in reality, measuring pressure differences inside the airbox in order to determine that "quality".
It stands to reason that under WOT there is no vacuum in the intakes on the sides of the engine, after the throttle body, (where they other MAP sensors are) ... In fact, just the opposite... Lots of boost down there. So the car looks to the other sensors in the air filter box to see if there is vacuum there, and there should be plenty of low pressure near the air filters, since the turbos are doing their best to suck in "high quality" air 😁. When those air box sensors are just out in the open in the engine compartment, they only see static atmospheric pressure (neither vacuum, nor boost), and therefore, due to this perceived "low quality" air filter intake condition under WOT (no vacuum whatsoever) the computer sets the P1CE700 and P1CE800 soft codes.
That's my theory anyway. Once it stops snowing where I live, and warms up a little, I'll be able to drive my car and see if the codes come back after I moved my sensors into the ends of the air filters of my Zac intakes.
I have to agree that they are a pressure sensor. Several people keep saying "air quality" sensor, but what does that mean? ... There is no sensor in the engine that tells you to get out of downtown because the air isn't as "high quality" as in the countryside. That sensor is only available in a Jaaaaag 😂.
Air flow through the airbox causes a change in air pressure inside the box (a vacuum). A clogged air filter would obviously flow less air and therefore have a different pressure reading than a clean air filter..... So even if you call them an "air quality" sensor they are, in reality, measuring pressure differences inside the airbox in order to determine that "quality".
It stands to reason that under WOT there is no vacuum in the intakes on the sides of the engine, after the throttle body, (where they other MAP sensors are) ... In fact, just the opposite... Lots of boost down there. So the car looks to the other sensors in the air filter box to see if there is vacuum there, and there should be plenty of low pressure near the air filters, since the turbos are doing their best to suck in "high quality" air 😁. When those air box sensors are just out in the open in the engine compartment, they only see static atmospheric pressure (neither vacuum, nor boost), and therefore, due to this perceived "low quality" air filter intake condition under WOT (no vacuum whatsoever) the computer sets the P1CE700 and P1CE800 soft codes.
That's my theory anyway. Once it stops snowing where I live, and warms up a little, I'll be able to drive my car and see if the codes come back after I moved my sensors into the ends of the air filters of my Zac intakes.
Took my car out for a spin today... Maybe 15 miles or so. Putting the sensors in the end of the air filters on my ZAC intake seemed to work... No codes. I guess the sensors were detecting the right amount of pressure drop.
