02 sensor or MAF sensor? Any insight?
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05 E55
02 sensor or MAF sensor? Any insight?
So, it seems as though my MAF went bad again. The first time the CEL went on, it threw a series of 02 sensor codes. But I read that a bad MAF meter can throw these codes.....so I took a chance and changed the MAF sensor and it the codes went away.
Now the light came back on and I'm getting P0150 - Bank 2, sensor 1. Could it be the 02 sensor or a MAF problem again?
Which leads me to my main question - Have any of you had a CEL come on and changed your 02 sensor and it went away?
Now the light came back on and I'm getting P0150 - Bank 2, sensor 1. Could it be the 02 sensor or a MAF problem again?
Which leads me to my main question - Have any of you had a CEL come on and changed your 02 sensor and it went away?
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From: Seattle
05 E55
Originally Posted by TresX
A faulty O2 sensor will trigger the CEL.
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1951 Caterpiller D6
I thnk someone posted someplace that with a bad O2 sensor the sensor position is singled out and a bad MAF the O2 code is not specific or something to that effect. If that is the case, it sounds like you might have a bad O2 sensor.
HTH
HTH
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A bad MAF will usually give you fuel trim errors....Can't recall the actual codes but there are two of them. If you have replaced your MAF recently, I would suspect an O2 sensor. (which you have 4 of) Only thing you can do is test each individual one to see which is bad.
Easy 02 test for DIYer is to hook the meter to sens sig wire and ground ... unplug sens sig wire feeding back to ECU ... leave sens heater wires connected ... warm car to normal...
Now , pull vac hose , creating a vac leak.. the sens should go lean
[ low v].... correct vac leak ... cuff the air intake, choking the engine and creating a rich mixture ... the sensor will see rich and read high.
When doing either of these , the meter should move as you open/close both vac leak or choke intake air..
All is you are doing is using the engine as a mixture tool and seeing if the sensor responds to your manually changing the a/f mix...that is why you do not want the wire feeding back to the ECU , as the ECU will try and correct your manual a/f mix inputs .........
you are looking for .1 to .9 volts, lean/rich , with a 1/2 sec change time...
that would indicate a decent sensor. A dead sensor will fluctuate very little and normally read .2 - .3v.
Easy 02 test for DIYer is to hook the meter to sens sig wire and ground ... unplug sens sig wire feeding back to ECU ... leave sens heater wires connected ... warm car to normal...
Now , pull vac hose , creating a vac leak.. the sens should go lean
[ low v].... correct vac leak ... cuff the air intake, choking the engine and creating a rich mixture ... the sensor will see rich and read high.
When doing either of these , the meter should move as you open/close both vac leak or choke intake air..
All is you are doing is using the engine as a mixture tool and seeing if the sensor responds to your manually changing the a/f mix...that is why you do not want the wire feeding back to the ECU , as the ECU will try and correct your manual a/f mix inputs .........
you are looking for .1 to .9 volts, lean/rich , with a 1/2 sec change time...
that would indicate a decent sensor. A dead sensor will fluctuate very little and normally read .2 - .3v.
Last edited by TresX; Aug 24, 2005 at 08:08 PM.
Thread Starter
MBWorld Fanatic!
Joined: Jun 2004
Posts: 1,880
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From: Seattle
05 E55
Good info fellas...and I'll give that a shot TresX.
By the way, how many of you have changed your O2 sensors and at what miles? Just curious as to when the typically go out...
By the way, how many of you have changed your O2 sensors and at what miles? Just curious as to when the typically go out...
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