L322 Accelerometer values

Graculus said:

A change in speed relative to, which is why the 'standstill' value isn't zero.
Edit: Actually, it's not a 'steady state', the rotational speed does vary, but it's the rotation that's important - it's a (relatively) constant vector acceleration.
Back to the sensors, they need to be able to measure acceleration or deceleration, hence the mid-range starting value. If it were possible to do it with resistors, it'd be a simple Wheatstone bridge array.

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Yes rotation of the earth from our perspective is a constant vector in space, but it's not acceleration. Acceleration is a change of speed or velocity, which is not happening to the car or us when stationary on the earth ! If the earth was changing speed we would have bigger issues than fixing cars !! It would require quite a large change in the 733mph for us to notice !!

Agreed the sensor probably has a non-zero output value when at rest or stationary, but the ECU should normalise this to zero so the numbers make sense !!

I rarely respond to double exclamation marks, however, for anyone else interested in the subject matter...

It references the values against a fixed value capacitor to determine the direction and rate of change.

If you have a read of the first link I found, the speed does vary, not significantly, but measurably.

Scientists reported that in 2020 Earth had started spinning faster, after consistently spinning slower than 86,400 seconds per day in the decades before. On June 29, 2022, Earth's spin was completed in 1.59 milliseconds under 24 hours, setting a new record.[3] Because of that trend, engineers worldwide are discussing a 'negative leap second' and other possible timekeeping measures.[4]

This increase in speed is thought to be due to various factors, including the complex motion of its molten core, oceans, and atmosphere, the effect of celestial bodies such as the Moon, and possibly climate change, which is causing the ice at Earth's poles to melt. The masses of ice account for the Earth's shape being that of an oblate spheroid, bulging around the equator. When these masses are reduced, the poles rebound from the loss of weight, and Earth becomes more spherical, which has the effect of bringing mass closer to its centre of gravity. Conservation of angular momentum dictates that a mass distributed more closely around its centre of gravity spins faster.[5]

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Clearly the mass of the earth changing speed will have some effect upon gravity, and therefore sensors designed to measure the rate of change of speed towards or away from the surface the vehicle is on, again, not a massive amount, but measurable - especially given that the control units calculate to eight significant decimal points.
Obviously I'm not saying that a small rotational speed change in the earth will cause the OP's issue, but it is worth noting there is a 'normalisation' routine available in later systems, I'm not sure if it exists in the earlier systems where the processing power is limited to the point of having to rely on height sensor inputs to be broadcast on HS-CAN rather than processed directly as in later systems.

It's also possible that the harshness is caused by capacitor ageing, particularly the reference capacitor in the control unit, or indeed defective dampers - or even a change in the wheel rim size not being updated in the CCF, I've found this to be the root cause in several instances with L405 / L494's in the past, I honestly can't remember if it's an editable value in L322 - it may be worth checking.

1.59mS over 24 hours is 0.0000018% so very slow acceleration, i.e. much less than 0.03m/s^2. Well less than 1/10th of the sensor reading. The diagnostic screen is wrong . . period !!

So after up dating the GAP I get these readings at standstill

J