You can use the cars battery or an external 12 volt battery. The source does not matter if the connector is disconnected from the solenoid valve as long as it is 12 volts and ground.

 

Hi Guys,

I think I've identified that it is the boost
sensor which is faulty. There is a good
strong vacuum in the hose connecting the
solenoid valve to the intake. There is
also NO vacuum connecting the boost
sensor to the selenoid valve, as babyhuey
mentioned to be the case.

Then I've removed the electrical connection
behind the boost sensor and checked the
voltage on the exposed pins on the sensor.
It was a bit confusing that there are three
pins rather than two, but in no combination
I was able to read a voltage value greater
than zero (irrespective of engine running
or not).

So it seems that the sensor is not generating
any voltage. Does that seem reasonable?

I think when the mechanic had changed the
boost sensor, he did not reset the check
engine light. Anyways the price he asked was
$300 (for the sensor only), which I think is sold
for around $200 online.

Thanks for all the help,
Oguz

 

You did not measure any voltage at either of the three pins??? That is not good but would not mean a bad boost sensor.Something does not sound right here.
Try these tests before condemning the boost sensor and spending the $200.

Engine running at a warm idle and all vacuum lines to boost sensor circuit connected.
Hook negative lead of voltmeter up to the negative battery post.
Disconnect the boost sensor connector, set meter to read ohms,and check for good continuity of wire that is Black w/yellow stripe to ground. kThis is sensor ground. Should be less than 10 ohms.
Now switch to volts and check wire that is Lightgreen w/ red stripe. Should be 5 volts. This is reference voltage from the PCM.
Now plug the boost sensor connector back in and backprobe the Lightgreen w/ red stripe wire to ensure that you still have 5 volts.
Now backprobe the wire that is Blue. This is sensor signal voltage. Should be between 2.37-2.88 volts.
Leave the backprobe in blue wire and then apply power and ground to the solenoid valve to allow vacuum to get to the boost sensor. Voltage should change to between 0.9-1.1 volts.
Did all of these tests pass and if not where was there a descrepancy??

 

Hi babyhuey and all,

Everything until backprobing the sensor seems
to work fine. The thing is I'm not sure how to
measure the voltage of the sensor.

It is a learning experience for me so let me try
to explain what I still do not understand. To
measure the sensor voltage, the sensor has to
be connected to the electrical harness, isn't it?

But when it is connected then all the pins get hidden
inside the harness which makes it impossible to
reach to them.

Backprobing seems like a technique to get around
this issue, but I don't know how to insert the leads
of the voltmeter behind the electrical harness. There
is just not enough space. Should I try to insert a
much thinner wire and measure the voltages at that
wire?

Thanks a lot,
Oguz

 

My millenia threw the P0105 code today.
I easily found it and changed it out thanks to the info here.
I would recommend a few things though:
If you thread a 6-32 or 8-32 tap into the broken tee that is stuck in the hose you can pull whats left out with relative ease.
You can get acceptable vacuum tees at autozone or CAP, but I would recommend turning them down, or cutting and then sanding off the barbs. They don't look like they really fit otherwise, and I suspect that if you cram the tee on with the barbs you will break something else.
It is a bit easier to replace the first tee that is under the miller cover if you remove the vacuum valve connected to the tee first.. take care.. that plastic is at least 12years old and living in a hot place; I did not break the mounting tab off mine, but I was suprised.

Thanks for the info all!

 

 

Can you send me some pictures of were the map/boost sensor is located at as well as the vacuum lines connect at a plastic tee thanks

 

You can find all sorts of stuff here:http://lucmorton.com/lucstuf/silly/m...nia-1996-1.pdf

The '96 manual matches most of the important bits on my 2000 Millenium Millenia.

Considering the age of millenias now, the most likely causes are the plumbing, rather than the sensors ( unless something mechanical happened to the sensor ). There is altogether too much plumbing under covers that retain heat. Even the better plastics can't cope with oil, heat, and vibration over time very well.

I tacked on the page with the vacuum diagram for the S.