SUM Calibration issues.....STILL

Re: SUM Calibration issues.....STILL (SilverSurf"R")

I believe the sensors range from 0-5v so sounds like they are reading in the correct range. Question is, are they the correct voltages. I'm trying to recall my factory training class in which we discussed 4C and I looked through my Course Books briefly but I can't locate the exact manual in which I remember taking level sensor readings. IIRC in VIDA there are signal description charts on Operating conditions. I don't currently have access to VIDA or I'd look it up for you. I know there are two level sensors in the rear and one in the RF. When the Springs were installed were the level sensors moved or otherwise possible switched? Or maybe the harness or connectors swapped? Lowering springs don't normally cause issues but as someone said, try and calibrate SUM with ride height @ stock (have tech put on lift).

If I remember I will try and look up in the R course manual any level sensor specs, if they are even there. That manual is at work and I won't get access until Mon. But VIDA does contain the spec ranges, it just takes a little know how to locate. Volvo Search in VIDA sux and you have to talk to it like you are a first grader. If I find something later, I will post. Gotta go cook dinner. Having Tacos! http://********************/smile/emthup.gif

Re: SUM Calibration issues.....STILL (rogersampson)

You are correct, if you believe the HELP files in the VID. I read these with the TECH and that is what they say..normal is about 2.5V.

AT REST - R = 3.5V, L = 1.5V

Whole car up about 4 inches, wheels on the ground R = 2.5V, L = 2.5V.
We never tried lifting one side and not the other.

Even at this height we got the same error code. Right Voltage to High, Left Voltage to Low.

My Tech is trying to Find another 04 R locally he can verify the readings and try to run the SUM calibration.

So I can surmise that the Help files in the VID are incorrect, or my Techs PC has a software glitch. But the problem is, no one seems to know what is correct.

Re: SUM Calibration issues.....STILL (SilverSurf"R")

If the suspension was at the midpoint, I would expect the feedback to be the same at 2.5, but with the car at rest the suspension is closer to the top of travel than the bottom.

I have spent some time under my car today and tried to depict what the sensors look like in this crude picture.

From all my years as an automation engineer the sensors look like simple potentiometers. And I can understand from the orientation why the voltages move in opposite directions as we saw with the VID on Friday. My car is a very early production model, 9/03 production date, and although this is not ideal for control I can under how it can happen from years in a prototype to production environment. Situations like this would be corrected in later production models and the software revised.
So, I hope my Tech can find an early 04 to compare this to so we can determine what the proper operation and corrective action would be.

She sure looks nicer lowered, but I am beginning to wonder if it is worth the hassle.

Re: SUM Calibration issues.....STILL (SilverSurf"R")

I found some old notes I had taken from earlier posts, and I now believe it is correct for one side to increase, as the other decreases, with the suspension being loaded or unloaded, as a unit. i.e not a case of one side raised and the other lowered. So with the new lower spings the system now thinks it is in a compression mode, and one sensor has increased by 1V and the other has decreased by 1V. I suspect this is normal. I do not know what range SUM calibration has, but it needs to establish this as the new static state, and in effect, calibrate it such that the sensors are at 2.5V. Of course you need to confirm there is sufficient travel up and down for the sensors. Worst case it could be done by lengthening or shortening the mechanical linkage to the the height sensors.

Re: SUM Calibration issues.....STILL (Oceans60R)

Checked the Course Code 0819 for the R.

Only thing it really mentions:

-The sensors are fed 5v from the SUM. The output signal from the sensors is approximately 2.5v when the car is stationary

-When vertical movements are detected, the signal will fluctuate around these values. The greater the movement, the greater the deviations.

-The SUM software contains diagnostic software for the position sensors.

Calibration
When a suspension module, shock absorber, or position sensor (rear) is replaced, adaptive data in the SUM has to be calibrated using VADIS

There's obviously more to it than that but without having VIDA and your vehicle to go over this step by step, diagnosing here on a message board will be very difficult. There are a few differences in the CAN starting with MY05 so having a '04 to compare to would be optimal, that is if the tech can't look up specs or diagnostic procedures in VIDA.

Have you tried a system reboot (aka disconnecting battery cables from battery and shorting them together for 10 minutes)? and then try the SUM Calibration. If the car is hooked up to VIDA, the Network reboot can be done under Vehicle Communication so no need to short cables.

If I find something else I will let you know.