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T6, What exactly does the ecu do with the map sensor

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T6, What exactly does the ecu do with the map sensor

Old 02-08-2011, 10:46 AM
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Join Date: Aug 2009
Posts: 39
Default T6, What exactly does the ecu do with the map sensor

I am asking because the car has both the map and maf sensors. I know for a fact that it is very sensitive to the maf signal. I troubleshot a maf on my car and came to the conclusion that simply cleaning the maf affected the signal enough to completely eliminate my check engine light.

I know the ecu has to use the map signal to determine the boost pressure so it knows whether to allow more boost to build, or if the boost has built too high, so it can trigger the check engine light for over/under boost.

What else does the ecu use the boost sensor for?
Old 02-09-2011, 01:07 AM
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Join Date: Aug 2009
Posts: 39

Well what I am wondering is that IF (and its a big if) the only thing the map sensor is used for, is to let the computer know what pressure the turbocharger is creating, then the signal from the pressure sensor could be slightly decreased to make the ecu think that the turbo has not created enough boost. Then the ecu should keep the turbo running till a little more boost is created. (just a little +2-4lbs, because there is not enough control over the engine)

Normally, I would not advocate doing this except the ecu seems like it may be sophisticated enough to handle this extra pressure. As it is, the ecu uses a maf, tps, lambda sensor, IAT, coolant sensor, ect ect... This is enough for most ecus to calculate fuel amount and duration, ignition advance and duration, and all other essential engine functions.

If the boost signal is not used for anything except to monitor whether the turbo pressure is too high or low. Its signal could then be modified to force the ecu to allow more boost without throwing a CEL. This could also work depending on how much the ecu modifies the engine controls based on the MAP sensor. For example, if the fuel maps are only massaged by 1% by the Map sensor, while primarily using the maf to calculate fuel delivery and ignition timing.

This whole thing is dependent on how much tolerance the ecu has for sensor values, does anyone have any info about the t6 ecu? I can't justify spending more to have the ecu flashed, than I spent on the whole car.
Old 02-09-2011, 08:47 AM
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Join Date: Feb 2010
Posts: 171

The boost pressure (requested vs actual) is constantly monitored in the T6. It is controlled via the TCV solenoid which actuates the wastgates on the turbos as a pair. Yes you could mess with the signal, but it may still throw a code as the flow over the MAF may conflict with the corresponding boost pressure range thats mapped into the ECU. Ie at WFO throttle, if reported boost pressure = x then the MAF should be between y and z, otherwise, CEL.

I'd avoid any sort of peformance upgrades unless you are already at stage 1 and dont have the GM transmission.

I'm pretty sure you can get an ECU upgrade from a reputable company for around $300. Heres a list of possible providers:


Last edited by NoLifeTilBoost; 02-09-2011 at 08:55 AM.
Old 02-10-2011, 12:31 PM
Thread Starter
Join Date: Aug 2009
Posts: 39

I'm not really interested in modifying my car, just knowing as many ways to do so as I can. As far as I can tell, the s80 uses a Bosch Motronic ME7 ECU. Off the top of my head I think the part number starts with 0 261.

Anyone care to comment or confirm? The Audi guys are using ME7 Ecus and have gone a long way towards reprogramming them at home. It looks like for the cost of a boutique ecu flash the tools and software can be purchased to allow as many reflashes as you need. I encourage everyone to try and learn as much about your cars as possible. its fun
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