It would appear that the official reply is that the Altimeter is neither use nor ornament

My first email was:

Dear Sir

I had my Mitsubishi Outlander Diamond serviced at ******* last Wednesday 9th September 2009.

Whilst it was being serviced a number of recalls were due to done and I asked for the altimeter to be checked as it was giving false readings. At sea level it was reading 550ft and in the Mersey tunnel (below the river) it was reading 200ft.

After a couple of hours I was told that all the work had been done but the mechanic did not know how to fix the altimeter fault.

After leaving the garage I found that the Altimeter has now stopped working and there is just a line of dashes for the readout.

Prior to taking the car to ******* I had asked at another Mitsubishi Dealership if the fault on the Altimeter had been seen on other vehicles? I was told that it had been known to occur and could be fixed under warranty.

Can you please advise me what can be done to remedy this situation.

Dealers reply:

Afternoon

I have looked at your email and we have checked with Mitsubishi technical regarding your problem this is the reply I got back from Mitsubishi technical department


The altimeter gets it's info from the barometric sensor. On a high pressure day it will show a lower altitude than a low pressure day. A difference of only 1 kpa in air pressure equals about 500ft in the altimeter reading. There is no way of resetting it on the MMCS. I'm not aware of any known fault or fix. Try comparing the reading on this vehicle with others on your site to see if the barometric readings are similar.

This reply comes from Mitsubishi head office and they are not aware of any fix in your email you mention another dealer knows how to fix the problem
If you could let me know what dealer and who you spoke to regarding the fault I will contact them.

Kind regards


My response


Dear Kevin

Thanks for looking into this for me.

It is an interesting reply and whilst the theory is partially correct. It is somewhat let down in practice.

All barometers do need to be calibrated at the altitude at which they are working. Or in the case of electronic devices, if calibrated at sea level i.e. zero feet they should be able to calculate the barometric pressure at differing altitudes.

Air pressure does vary according to altitude however altitude is a fixed measurement. ******* garage is 6m (approx 20ft) above sea level whatever the barometric pressure happens to be.

As the GPS calculates the vehicle position in 3D why is this not also used for the altimeter?

The dealership I mentioned in my earlier email was ********** where I spoke to their Service Manager.

Even if I were to allow for altimeter to be so inaccurate that it is in fact useless. This would not alter the fact that after the vehicle was worked on at ********* the altimeter ceased to work at all for a couple of weeks and now only works intermittently. Therefore there is obviously a fault which need to be rectified.

Regards

Todays reply

Phil

I have checked with the technician who worked on your vehicle he made no adjustments to your car as he could not find any way to adjust the altimeter

I have had a 2nd reply back from technical and the response is below we are happy to replace faulty parts under warranty but we need to know which parts are faulty if any
We have checked 2 other vehicles on site both had just lines on the altimeter when checked in workshop

The response from Mitsubishi technical regarding the operation of the alimeter

Barometers will need calibrating to the altitude at which they are working but in the majority of cases they are fixed and are used for weather forecasting. Altitude measurement is not the primary use of these. Problems will arise when they are used to measure altitude. The accepted nominal pressure at sea level is 1013 mb which equates to 0 feet, in a perfect world where atmospheric pressure only changes due to altitude and not the weather a barometric altimeter could be calibrated to this and be accurate at any altitude. In reality though, at sea level, commonly observed pressure readings range between 970 mb and 1040 mb. This equates to an altitude of more than 800 ft above sea level to over 500 ft below sea level. Actual values of atmospheric pressure vary from place to place and from hour to hour, so using ********* as an example, as a weather front comes over the altitude shown on the MMCS will alter. This is purely an affect of the way the system works on these vehicles, they are not designed to be accurate enough to fly with and the readings in the vehicle jump in 200feet/50 metre steps. It is a valid point as to why the GPS system is not used for the altitude calculation but as mentioned above there is no reason for such an accurate reading in a motor vehicle. I expect that as a barometric sensor is fitted to these vehicles to help control the fuelling it was a simple step to use the information from this to give a basic altitude reading.

Regards

Kevin

 

Mitsubishi is absolutely rigth concernig this ALTIMETER ISSUE. As why they didn't use GPS for altimeter readings, the most obvious answer is that GPSs though highly accurte for LAT/LON positioning are notoriously innacurate for height positionig (try any hand held gps), so is better to have readings from a barometric pressure sesnsor
..and for all newcomers, new and old owners, etc...., the opening on bottom of the MMCS is for inserting a hardware "key" when updating maps and software of the MMCS...