P38 EAS rises automatically

Hi all,

Is there any common fault where the suspension rises automatically during a normal trip?

Mine does that and never stops until I press the down button. Sometimes, if I let it go, the balloons get so inflated that the car bounces like he has steel bar shocks.

I opened, measured and swapped from sides the all 4 heigh sensors.

Any suggestions to narrow this?

Get yourself the software and cable, connect up to a laptop and read the faults.
CD and cable available on ebay or a couple of the lads on here. Datatek springs to mind.

Hi Rfsimoes, I agree with DB, depending on which year you RR was built the sensors could handed and can't be swapped, and if you've "opened" them, they now maybe damaged beyond repair.

Also if you had filled out your "UserCP>Your Profile" with your location. There might be a member with the lead/software close to you, willing to give a hand, but as you haven't we don't know if to offer or not.....

It's your eas driver pack or air pressure sensor playing up.

That sounds like a driver pack problem to me. As said you need to get the fault codes read. If you have indeed opened the height sensor and they are like mine, then you have fecked them, you will never get them back together and watertight.

Hi,

Thanks for the reply s.

I have RSW free software and made the cable that I use to calibrate. Is that enough to read the faults?
Is that I always have faults so I just ignore them. I tout it was just like that.

Looking at sensors insides I realised that they could be swapped to benefit from a unused resistor part. check atachement.

After this work on the sensors all is working just like before, fault and everything.:doh:

rfsimoes said:

Hi,

Thanks for the reply s.

I have RSW free software and made the cable that I use to calibrate. Is that enough to read the faults?
Is that I always have faults so I just ignore them. I tout it was just like that.

Looking at sensors insides I realised that they could be swapped to benefit from a unused resistor part. check atachement.

After this work on the sensors all is working just like before, fault and everything.:doh:

Click to expand...

The only fault you should see that you can ignore is:- "vehicle has moved" any other fault reported requires diagnosis and attention. How did you put the lid back on your sensor and guarantee it's watertight? If it's not watertight, the first time you hit a big puddle you will be in trouble
List the faults you get

I ignored the faults because I was getting allot of errors while calibrating the sensors because I was using windows 7 and a usb to rs232 adaptor which I found useless for this aplication.
Now, With my good old xp laptop I read the folowing errors:

6 : RR signal incorrect
7 : Vehicle has moved

I then pressed Unlock EAS, Ignition of and on, and the errors are gone.
I think I will read the faults more often now to see if the error comes back...

Hi!

It looks like a Driver pack error...

If I was you,
First I check the "RR signal incorrect";
Second, I will rebuild your Block Valve

I had the same problem, but it was the new diaphragm that I put...

Whilst stuck in traffic on the m5 this afternoon, mine decided to keep doing this too. I had the inhibit switch set so it couldn't actually move but it kept randomly selecting off road height.

So is the consensus of opinion that it's a driver pack problem? It just appeared to be as though someone had selected off road height. Rocking the height switch cancelled the height change and no errors are reported. It's very odd. I'm wondering if the height switch is faulty.

Still, with all my other eas problems this weekend, who knows!

Sorry Guy, that definately sounds like a driver pack.

Datatek said:

Sorry Guy, that definately sounds like a driver pack.

Click to expand...

Hi Keith,

Been thinking about this a bit and I can't see how the driver pack could cause this problem. Surely it just converts the digital signals from the EAS Ecu to waveforms that can directly operate the solenoids in the valve block. How on earth could a fault in here cause uncommanded height changes? I'm sure you're right but I can't see how it would work.

My fault seems to be as though someone has selected off road height. No faults logged and it goes back down again when commanded (although I did have 2 seemingly unrelated faults in a row a couple of days before). Time to get my kicker repaired I suppose.

It's not done it again since but I've got to drive back from Wales with a trailer on Thursday so I expect it'll wait until then before throwing another hissy fit.

kooky_guy said:

Hi Keith,

Been thinking about this a bit and I can't see how the driver pack could cause this problem. Surely it just converts the digital signals from the EAS Ecu to waveforms that can directly operate the solenoids in the valve block. How on earth could a fault in here cause uncommanded height changes? I'm sure you're right but I can't see how it would work.

My fault seems to be as though someone has selected off road height. No faults logged and it goes back down again when commanded (although I did have 2 seemingly unrelated faults in a row a couple of days before). Time to get my kicker repaired I suppose.

It's not done it again since but I've got to drive back from Wales with a trailer on Thursday so I expect it'll wait until then before throwing another hissy fit.

Click to expand...

What happens I think is random switching of a transistor in the driver pack without an input from the ECU which causes one valve to operate, the ECU then commands the others to keep it level. If you had logged a fault from a height sensor then it would be that and not the driver pack.

Datatek said:

What happens I think is random switching of a transistor in the driver pack without an input from the ECU which causes one valve to operate, the ECU then commands the others to keep it level. If you had logged a fault from a height sensor then it would be that and not the driver pack.

Click to expand...

Hmm. Seems odd that the ecu would treat an event like that as a commanded height change though.

Presumably 2nd hand driver packs are a waste of time?

kooky_guy said:

Presumably 2nd hand driver packs are a waste of time?

Click to expand...

The driver pack isn´t cheap, but it depends the price for the 2nd hand...

Before you spend money, try before to clean the contacts in the EAS ECU.
(In LHD RR is under the driver seat)...... Who knows ???

kooky_guy said:

Hmm. Seems odd that the ecu would treat an event like that as a commanded height change though.

Presumably 2nd hand driver packs are a waste of time?

Click to expand...

It doesn't take it as a commanded height change, it just tries to keep the car level based on the sensor readings. If one is going up the others have to follow for safety.

Datatek said:

It doesn't take it as a commanded height change, it just tries to keep the car level based on the sensor readings. If one is going up the others have to follow for safety.

Click to expand...

That makes sense but on the display, the off road height was flashing and the up arrow on the dash was illuminated as though the height change was a normal commanded one. It's a bit weird.

kooky_guy said:

That makes sense but on the display, the off road height was flashing and the up arrow on the dash was illuminated as though the height change was a normal commanded one. It's a bit weird.

Click to expand...

That I would expect to be a height sensor, but you say no faults recorded? I suppose the ECU might do that for an uncommanded rise to indicate a problem.

Hi All, I have just bought another P38, but a 4.6 this time.. It was sold to me with an EAS fault described as "it goes up and down alot" and that "I mustve plumbed it back in wrong after replacing the pipes"

Mine keeps selecting Wading height of its own accord, and wont raise or lower all springs at the same time (maybe 9 times out of 10.) If you leave it to rise and rise, you get a "RR Sesnor out of range," a "Unable to lower RR" and a "RR Valve stuck closed"

I have replaced the Driver pack and Valve block to no avail, swapped over the EAS Relay, now i'm looking at dismantling and cleaning the RR height sensor.

Any more thoughts? I'm a bit stuck on this one!

I have used EASunlock to try and recalibrate, (the achieved heights are a little different to the stored ones)

Cheers

They never do raise and lower all at the same time. The rear always goes up first then the front. So the car does not dazzle if the lights are on. The front will always drop first then the rear. For the same reason. I would say RR sensor is knackered. Check the plug to it is good contact wise. The connections maybe dirty.