# Map sensor-



## wildcard (Nov 18, 2015)

Hi
I have a 2012 Chevy Cruze ECO 1.4 engine an 4 days ago the service engine light came on. I had a computer hooked up to it and it read a code that the map sensor was bad. So I had it replaced today(did it myself as it was really simple)and I test drove it and amount 5 miles into the drive the engine light came back on. Had it retested and the map sensor code came back up. Went took the sensor back got another one and installed that one and on that test drive we were able to drive about 30minues this time before the light came on. Any suggestions on what might be going on here? The car was bought used and no warranty so a dealership is out. Also the map sensor code was the only code that came up both times it was tested.

BTW the car was at about 50,300 when the light came on.


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## Robby (Mar 1, 2013)

What is the actual code # being held in memory......if more than one, what order are they in?

Rob


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## spacedout (Dec 7, 2010)

The map sensor monitors boost, maybe there is an issue with the turbo causing a low reading.


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## Robby (Mar 1, 2013)

If I may go further, the MAP or Manifold Absolute Pressure sensor relays negative or positive manifold pressure.
The manifold has positive pressure on boost, negative pressure (vacuum) while idleing or deceleration or steady speed.......Absolute pressure.

The low boost situations we've heard of are called 'Implausable'........meaning the boost the ecm anticipates is below a pre determined threshold......there is a specific code for this........the ecm anticipates a positive pressure of X, as reported by the maf but it is recieving Y.....a turbo code is the result.

A maf fail code means the information is not being provided.....A diaphram, vacuum source, or electrical failure of the unit.

That's why I was hoping the OP would give the codes in order.

Rob


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## jblackburn (Apr 14, 2012)

Look for a blown-off turbo/intercooler hose.

Edit: Actually I seem to remember someone saying that their pipe to the throttle body had deformed around the sensor as well and was causing a leak there, so something else to look into.


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## roadrunnerA12 (Jan 21, 2015)

In other words, always do the old school mechanic stuff first before hooking up the code scanner - check for vacuum leaks from cracked hoses, disconnected hoses etc. Check for pressurized air escaping on a turbo car like Ron White said. If you hear a ticking noise or knocking noise under the hood, use a mechanic's stethoscope to track it down. If you don't have one of those, use a short piece of garden hose and put one end on different areas of the engine while holding the other end to your better ear.


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## spacedout (Dec 7, 2010)

roadrunnerA12 said:


> Check for pressurized air escaping on a turbo car like Ron White said.


I don't know why butI laughed my ass off when I read that, almost spit out my coffee.


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## obermd (Mar 3, 2012)

roadrunnerA12 said:


> In other words, always do the old school mechanic stuff first before hooking up the code scanner - check for vacuum leaks from cracked hoses, disconnected hoses etc. Check for pressurized air escaping on a turbo car like Ron White said. If you hear a ticking noise or knocking noise under the hood, use a mechanic's stethoscope to track it down. If you don't have one of those, use a short piece of garden hose and put one end on different areas of the engine while holding the other end to your better ear.


I would do both and use the first code logged to guide me for the physical search for issues.


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## wildcard (Nov 18, 2015)

THanks for the heads up guys. Sorry I don't remember the exact code that came up and it was only the map codes sensor. So I'm going to bit the bullet and take to the dealership and see what they find. I will ask them to check all the hoses and such around the sensor


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## sixtyin3 (Apr 1, 2012)

My car did the same thing. A bad PCV valve (valve cover assembly) shot oil threw the system and wiped the sensor out.

Changed the sensor, still ran like crap. Changed the cover and it was fixed.


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