P0107: MAP/BARO Circuit Low Input

[Smith1000]

I have a '97 Lesabre that is running great, but had an engine code recently. The code is P0107, MAP/BARO Circuit Low Input. The car runs fine, but the code has registered twice. Has anyone seen this code before in a Lesabre? Thanks.

[BNaylor]

Typically a P0107 DTC is a bad MAP sensor located at the right hand side of the UIM over the PCV. The PCM module has detected either a constant short to low or an open either in the signal circuit or the MAP sensor itself. It won't hurt to check the PCM 5 volt low reference signal at the input wire of the electrical connector first to make sure it is getting the reference signal. Easy part to replace or control substitute with a known good one but may be up there in cost.

[Blue Bowtie]

You'll also want to inspect the bushing which seals the MAP sensor stem to the intake plenum. If the bushing is deteriorated and leaking, the MAP reading will be consistently low.

[BNaylor]

Actually for that respective DTC to set it is just not low as far as actual manifold absolute pressure but way off electrically via either an open or short. The PCM module is alot smarter than we are.

Signs of a bad MAP accordian seal is oil dripping from the plastic forked holder and the PCM detecting actual low or out of range MAP per what is programmed in since it has to look at the desired values. In other words other DTCs should be present if that were the case, the most notable is the EGR valve flow test will fail generating a P0401 DTC.

Here is an old MAP sensor out of a Series II 3800 engine that I saved in my bad parts bin. Incidentally, it generated a consistent P0107 DTC.

[HotZ28]

[quote BNaylor]Actually for that respective DTC to set it is just not low as far as actual manifold absolute pressure but way off electrically via either an open or short. The PCM module is alot smarter than we are.[/quote]

Conditions for Setting the DTC
The MAP sensor voltage is less than 0.10 volt for more than 4 seconds.
Based on the above, I agree that this is much more than a vacuum leak!
If reference voltage checks OK, time to replace the MAP sensor.

[BNaylor]

And I agree with you Bo.............

Of course we die hards would run an engine vacuum test just to be sure. As far as basic performance on this MAP sensor and voltage on the output to the PCM module about 2.0 volts at deceleration closed throttle - high engine vacuum and 4.0 volts at WOT low engine vacuum. And I forgot to mention when that accordian seal seen in the pics really gets bad you'll see low engine vacuum on the vacuum gauge (0-30 in-hg) type and around the MAP sensor area may hear this hissing or buzzing sound. Best part is this DTC is not a bad one to have since it doesn't affect driveability but should be corrected nonetheless. PCM just reverts to default values and other engine parameters. Like I said earlier smart!

[Smith1000]

The bushing is coming apart. It is probably time for a new sensor. Thanks.

[Blue Bowtie]

Try a new seal first, then see if the PCM is smarter...

I'll wait.

[BNaylor]

I thought it was a bushing. ......

The seal is an integral part of the MAP sensor based on the way it is manufactured and not available separately therefore the MAP sensor must be replaced in it's entirety. The way it mounts in the plastic bracket and inserts into the top of the PCV valve precludes any vacuum leaks and it is an accordian seal so it compresses.

And it is not the cause of the P0107 DTC. As suggested the OP needs to check the PCM 5 volt low reference signal first at the electrical connector input. If that is good then the MAP sensor is the next likely possibility. But the output of the MAP should be checked and it must be greater .1 volts. If the MAP doesn't resolve the issue then the problem is wiring to the PCM module or the PCM module itself.

[happydog500]

My MAP Sensor went out. I ordered from the internet. Mine came with OUT a rubber piece (Local Parts store called it a "grommet").

The picture from the site showed the rubber grommet but when I emailed them back, they told me the picture was for "illustration purposes only."

I used the one from my old one just to get it to fit in, but it is in very bad shape. Plus, I used a grinder to grind off the end plastic piece and grinded the rubber.

Any suggestions on what I can do? I was wondering if anyone had one out there that they could give me? What can we do to work out for me to get it?

Please give this a thought,
Thank you,
Chris.

[BNaylor]

Originally Posted by happydog500

My MAP Sensor went out. I ordered from the internet. Mine came with OUT a rubber piece (Local Parts store called it a "grommet").

The picture from the site showed the rubber grommet but when I emailed them back, they told me the picture was for "illustration purposes only."

I used the one from my old one just to get it to fit in, but it is in very bad shape. Plus, I used a grinder to grind off the end plastic piece and grinded the rubber.

Any suggestions on what I can do? I was wondering if anyone had one out there that they could give me? What can we do to work out for me to get it?

Please give this a thought,
Thank you,
Chris.

What internet site or supplier did you purchase the MAP sensor from? That doesn't sound right.

You may have been short changed. I know for a fact the OEM AC Delco and aftermarket Wells/Duralast (Autozone) MAP sensors come with the seal or grommet, whatever we desire to call it. That is a one of a kind or unique part. Even Dorman doesn't market just the seal and I don't recall it being available from a GM dealership or AC Delco supplier separately.

The MAP sensor seal I posted in my pic is serviceable and probably in better shape than yours. Just send me a PM message with your mailing address . I'll remove it and mail it to you by first class USPS. Reminder: No not post private info in a post.

I recall you had alot of issues with your LeSabre. How did you determine you have a bad MAP sensor and what was the odb-ii DTC, if any?

[happydog500]

When we changed the U & LIM, when taking the MAP out, it broke in half. After that, when I started it, it ran at a high idle and wouldn't go back down.

Your right, you can't buy the rubber piece anywhere. That's what makes me mad.

The place I ordered it from was, "Global Automotive" on eBay motors.

They kept my money for two weeks before they shipped. I was waiting all that time not being able to drive. When I finally got it, I couldn't use it. I had to search around the stuff in the (friends) garage and was glad to find it before we cleaned up and through stuff away.

My very reliable car, isn't running right now. Turns over but doesn't start.

Na-na-na-na-na-na-na-na, nothing. Befroe it did this, when driving slow, sometimes it would intermittently sputter and slow down to a crawl. Once I got back up to speed it would go OK for a while.

Waiting to find someone with a fuel presser gage to see if I have fuel presser.

Someone told me to switch the wires on the fuel pump and run it in reverse for a few seconds. that cleans and makes them work again. I am a frade to do that. I'm not about to switch wires on the gas tank and turn it on for a few seconds.

Thank you,
Chirs.

[Blue Bowtie]

And if Mr. Naylor's gracious offer of his spare bushing isn't the correct fit, I have another spare which is 0.227" I.D. and fits a 0.437" bore, if that will help you. It's still reasonably pliable.

Sorry if I "jinxed" you by all this talk of seals, grommets, and bushings, but it seems that's the case.

[Smith1000]

I picked up a new MAP sensor today. The parts store said they listed 3 different numbers for a MAP sensor for a 97 Buick. I didn't have the OEM number on me, so I looked at the 2 they had in stock. They looked identical. I wrote down the 2 numbers for the ones in stock and bought one of the sensors.

I am home now and neither of the 2 numbers match the number on the original sensor. The sensor looks just like the one in the car though, although the new one is by BWD.

Does anyone know why they list 3 numbers? What's the difference? I am wondering if this one will actually work. I can return it, but not if I have installed it. I have looked at some on-line auto parts stores and they only show one MAP sensor listing for a '97 Lesabre.

They did not sell the rubber grommet separate from the sensor.

[happydog500]

Not sure on the MAP, but I do know in the middle of 97 they changed somethings so an "early" has one part and a "later" has another.

Like I said, not sure what's going on with the MAP #, just that there IS some things on a 97 I've ran into that's split in the year.

The place where you bought it should be able to tell you what the difference is, or what one you need. How could they not know what part you need at a place that's selling you a part.

If not, try another place, ask them to see what they say. If they list only one, ask back at the (3) place that no one else does that.
Hope this helps in any way. Sorry if it doesn't.
Chris.