Barometric pressure sensor

[cubanman2]

Does the 93 sc400 have a barometric pressure sensor and if it does where is it located?

 

[Peewee]

I seriously doubt it, but if it does, it will be in the AFM

 

[Zuffen]

Most barometric sensors are stand alone. For example Porsche mounted their's under the passenger seat. If it was in the AFM it would be affected by the rising and falling pressure as the throttle opened and closed.

I've had my ECU apart and they don't have a sensor in there. They are usually easilly identified.

I would expect a side effect of the the VKV AFM is it doesn't need a sensor.

 

[Lambo]

This is from an article i found maybe it helps

Both Toyota/Lexus and Mitsubishi Karman-Vortex
air-flow sensors put out two signals: an air-flow
frequency signal and an air-temperature or
barometric-pressure voltage signal. The Karman-
Vortex signal should be a square-wave signal that
flips back and forth from 0 to 5 volts. The frequency
of the signal will increase (narrower pulse width)
as air flow increases. Frequency should increase
smoothly and steadily with rpm.

Regards
Lambo

 

[Deuce]

According to my factory ls400 manual, the ecu has what is called a "High altitude compensator sensor"(HAC). The sensor is used to detect atmospheric (absolute) pressure.Changes in air pressure cause changes in air intake density and therefore the air-fuel ratio. The ecu uses this input to make corrections for these changes in air pressure. If the ecu records a diagnostic code "35" it goes to fail safe and the atmospheric pressure is set at 760mm Hg.This HAC sensor is built into the ecu and I have no idea where it is located. Hope this helps.

 

[Lambo]

Hi Cubanman, you say you have a sc 400 the circuit i have shows the ecu and afm for that model , i suspect the resistor with the circle around it in the afm up in the right of the circuit is the temporature sensor, as this is the standard electronic symbol for a temporature varied resistor, different manufactures do it other ways Mitsubishi have a Diode inside the afm on my old Mitsi starion, and the circuit shows nothing like a barametric sensor in the main ecu diagram. Circuit file is to big to attach. could pm
Best Regards
Lambo

 

[cubanman2]

Lambo can you PM it to me please. I want to thank you all for the info.

 

[Deuce]

There seems to be some confusion between a MAP sensor and a Barometric sensor. If you are looking for a MAP sensor you won't find one as a Karmann Vortex is used for the AFM.

 

[cubanman2]

Im not looking for a MAP sensor.

 

[Lambo]

cubanman2, could not get the pdf to attach to a pm have a look at the file attached on my previous post.about 4 posts up from here.
Regards
Lambo

 

[cubanman2]

The BARO is located in the ECM. I just looked at a mechanic book and it says it is located in the ECM.