P38A EAS what am I missing?

oakey · Jun 26, 2022

1995 Gems
Changed RR sensor as kept faulting on rough roads.
Has not been calibrated since.
RR, the new one, set point 109 actual 112 but visually far far too low
RL, the original, Set point 109 actual 83 and is quite happy there

No leaks.
What am I missing? Must be something obvious but I am b**ggered if I can find it

awkwardbob · Jun 26, 2022

No idea, but I feel your pain…

Could it be a calibration issue ?

oakey · Jun 26, 2022

If it needed calibrating then she would go to set height which could be too high or low

awkwardbob · Jun 26, 2022

oakey said:
If it needed calibrating then she would go to set height which could be too high or low

Not necessarily, the numbers are arbitrary to an extent are they not ?
It ‘thinks’ it’s at the right height (the numbers are where they should be) but this doesnt actually correspond to the actual height.

I need to do mine too and I think it’s a case of getting the wood blocks out.

-of course I could be very wrong, in which case I’m happy to be corrected

oakey · Jun 26, 2022

Yes the numbers are arbitrary but she should go to that height or bit count.
Next xtep is calibration but I dont think it will cure it.
I will find out lol

RangeRoller dt · Jun 27, 2022

How old are the shocks?

awkwardbob · Jun 27, 2022

oakey said:
Yes the numbers are arbitrary but she should go to that height or bit count.
Next xtep is calibration but I dont think it will cure it.
I will find out lol

Good Luck ,

Datatek · Jun 27, 2022

After a sensor change, it always needs calibrating. The sensors are not precision devices.

oakey · Jun 27, 2022

Thanks for replies
Shocks are about 50k
No not precision but why is it not going to the desired height?
I accept the height will be wrong but it should go to the desired set point?

awkwardbob · Jun 27, 2022

But isn’t the only reference it has the bogus numbers from the height sensors ?

ie. It thinks it needs to get to 115 so it goes to 115 regardless of how high that actually is .

mind you, is t it supposed to ‘sophisticatedly self-level’ ?

oakey · Jun 27, 2022

But it only goes to 83 when set point is 115

awkwardbob · Jun 27, 2022

Ah !
Sounds like mine

Datatek · Jun 28, 2022

oakey said:
But it only goes to 83 when set point is 115

Bad connection, corroded connectors at the foot of the A post or a duff sensor.

pwood999 · Jun 28, 2022

Nanocom & EAS Unlock comms to EAS are slow, so the values might not be in real time. If target is 115, and actual is 83, then the corner hasn't had enough air to rise fully.

I generally disconnect the valve block from ECU & drive the heights manually while watching the values from the ECU diags. Then I can manually adjust to calibrate without the ECU trying to override & adjust. Simply apply 12V to driver pack inputs such as Inlet & Corner to adjust that airbag, and watch Nano actual value.

Datatek · Jun 28, 2022

pwood999 said:
Nanocom & EAS Unlock comms to EAS are slow, so the values might not be in real time. If target is 115, and actual is 83, then the corner hasn't had enough air to rise fully.

I generally disconnect the valve block from ECU & drive the heights manually while watching the values from the ECU diags. Then I can manually adjust to calibrate without the ECU trying to override & adjust. Simply apply 12V to driver pack inputs such as Inlet & Corner to adjust that airbag, and watch Nano actual value.

That advice sounds like it could be dangerous in the wrong hands. I have never checked, but I thought the signal inputs to the driver pack were 5 volts as is usual for logic driven devices.

pwood999 · Jun 28, 2022

No the inputs on pins 1-6 are all 12V. (This is how my manual control box works.)

All that's required is the following (make sure tank is full & pump not running)

12V to pins 12 & 13, and Ground on pins 10 & 11. This makes driver pack active with no input from ECU
Then to raise any corner(s), do any of these in pairs or individually:
- To raise Rear Left apply 12V to pins 1 & 5
- To raise Rear Right apply 12V to pins 2 & 5
- To raise Front Left apply 12V to pins 3 & 5
- To raise Front Right apply 12V to pins 4 & 5
To lower corners, use pins 1-4 and pin-6 for exhaust.

oakey · Jun 28, 2022

Thats very technical thank you
May well give it a shot.
May be a duff sensor and I havent soldered the cables in the A post yet but I thought the sensor wires went straight to the ECU?

pwood999 · Jun 28, 2022

Sensors do go direct. Footwell connections impact reliable diagnostic & height switch.

manual adjustment makes it easier to check sensors throughout their range for sensible readings & calibration

Datatek · Jun 29, 2022

pwood999 said:
No the inputs on pins 1-6 are all 12V. (This is how my manual control box works.)

All that's required is the following (make sure tank is full & pump not running)

12V to pins 12 & 13, and Ground on pins 10 & 11. This makes driver pack active with no input from ECU

Then to raise any corner(s), do any of these in pairs or individually:

To raise Rear Left apply 12V to pins 1 & 5

To raise Rear Right apply 12V to pins 2 & 5

To raise Front Left apply 12V to pins 3 & 5

To raise Front Right apply 12V to pins 4 & 5

To lower corners, use pins 1-4 and pin-6 for exhaust.

View attachment 268274

You can do all that via the EAS diagnostics without all the hassle. In the heights TAB of the RSW EAS software, he height of each corner can be adjusted up or down with no ECU interference, when the measured heights are correct, write down the numbers and write them back. No connecting or disconnecting required.

pwood999 · Jun 29, 2022

Agreed, but I thought the OP also had intermittent diagnostic connection ?

P38A EAS what am I missing?

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