Sorry - Yet another EAS question!

kernowdragon · Mar 6, 2011

My EAS has been faulting out over the past couple of weeks, and despite plenty of experience and success resolving issues in the past I'm not having any luck this time.

The problems started after a splash through a large puddle, resulting in showing a front pass side sensor error. After drying out and wd40'ing the sensor all appeared well for a few days, however it then started faulting again only with a blank fault log. The problem only showed whilst on the move, the car operated fine when stationary, going up and down on command without issue.

I checked for leaks without finding any, replaced pump with a known good one, and then valve block with a rebuilt one, all without making any improvement. Now the car is refusing to lift at all on the pass side, however the other side is rising, yet it is reporting having hit the target height? although the sensor heights on the drivers side reported are higher than they should be for the setting, presumably trying to compensate for the other side? Is there a common point in the wiring for the pass side front and rear sensors? Or might the lack of any recorded faults suggest the ECU is to blame? Any help will be greatly received?

Datatek · Mar 6, 2011

kernowdragon said:
My EAS has been faulting out over the past couple of weeks, and despite plenty of experience and success resolving issues in the past I'm not having any luck this time.

The problems started after a splash through a large puddle, resulting in showing a front pass side sensor error. After drying out and wd40'ing the sensor all appeared well for a few days, however it then started faulting again only with a blank fault log. The problem only showed whilst on the move, the car operated fine when stationary, going up and down on command without issue.

I checked for leaks without finding any, replaced pump with a known good one, and then valve block with a rebuilt one, all without making any improvement. Now the car is refusing to lift at all on the pass side, however the other side is rising, yet it is reporting having hit the target height? although the sensor heights on the drivers side reported are higher than they should be for the setting, presumably trying to compensate for the other side? Is there a common point in the wiring for the pass side front and rear sensors? Or might the lack of any recorded faults suggest the ECU is to blame? Any help will be greatly received?

First off, WD40 is not suitable as an electrical cleaner.
I would say the sensor is shot. Within limits, the EAS seems to try to accommodate a dodgy reading from a single sensor. The "O" rings on the sensor shaft fail which is where the water gets in, I posted pictures a while back showing a failed "O" ring.
The sensor has a fixed resistance value as well as a variable value, I reckon that the EAS thinks it's at the correct height.

woogoo · Mar 6, 2011

Can I suggest you check to see if the sensor arms aren't bent, or it hasn't come loose on its mountings, as this may explain the odd behaviour.

gtland · Mar 6, 2011

Going up and down by itself can be a failing driver pack. I think you can only check by substitution? Would be happy to be corrected on that tho`!

kernowdragon · Mar 8, 2011

Datatek said:
First off, WD40 is not suitable as an electrical cleaner.
I would say the sensor is shot. Within limits, the EAS seems to try to accommodate a dodgy reading from a single sensor. The "O" rings on the sensor shaft fail which is where the water gets in, I posted pictures a while back showing a failed "O" ring.
The sensor has a fixed resistance value as well as a variable value, I reckon that the EAS thinks it's at the correct height.

Thanks Datatek, the wd40 was purely chase out any moisture, I've been back over it with switch cleaner since. I reckon it must be one of the front sensors tho (or possibly even both), FL is reading constantly higher than normal, FR consistantly lower than normal. Assuming one side is trying to compensate for the other, it would seem more likely that the lower reading one is at fault??

woogoo said:
Can I suggest you check to see if the sensor arms aren't bent, or it hasn't come loose on its mountings, as this may explain the odd behaviour.

Thanks woogoo, everything appears straight and secure.

gtland said:
Going up and down by itself can be a failing driver pack. I think you can only check by substitution? Would be happy to be corrected on that tho`!

Thanks gtland, tried replacement driver pack without any difference.

Datatek · Mar 8, 2011

I would not assume anything of the sort. Put a multi meter set to Ohms on the sensor and move the arm slowly through it's full travel and look for jerky changes in the reading.

kernowdragon · Mar 8, 2011

Didn't have access to my meter, so went for reversing the sensors side for side so they act on fresh sections of the resistance track, and bingo, back to normal. So will sort a new set of sensors in due course.

Datatek · Mar 8, 2011

kernowdragon said:
Didn't have access to my meter, so went for reversing the sensors side for side so they act on fresh sections of the resistance track, and bingo, back to normal. So will sort a new set of sensors in due course.

Result! Don't leave changing them for too long, there is very little difference in the wear area when you swap them over

wammers · Mar 8, 2011

"Thar yah go". As good old John Wayne would have said. Let others take note, when funny things happen at the front end of your car. Don't change the driver pack, don't change the O' rings in the valve block. Check the bloody sensors 9 times out of 10 that will be the problem.

Datatek · Mar 8, 2011

wammers said:
"Thar yah go". As good old John Wayne would have said. Let others take note, when funny things happen at the front end of your car. Don't change the driver pack, don't change the O' rings in the valve block. Check the bloody sensors 9 times out of 10 that will be the problem.

Amen to that

kernowdragon · Mar 9, 2011

Datatek said:
Result! Don't leave changing them for too long, there is very little difference in the wear area when you swap them over

Maybe I'm missing something but it would make sense that apart from at max extension the wear areas are actually totally opposite. The part number is identical for each side therefore the resistence track is symetrical. The linkage is fixed to the armature shaft of the sensor, therefore the sensors armature sweeps the same angle as the linkage travels. The sensor has a total range of around 240 degrees of travel. On one side it moves from the top of that range through approx 120 to dead bottom at max suspension travel. Reverse the sensor and it's acting on a totally new piece of the track, except at the very bottom.

kernowdragon-albums-odds-n-sods-picture5850-sensortrack.jpg

Datatek · Mar 9, 2011

Have a look at this thread "Height Sensors Useles Info". sorry can't make a link work.
At normal ride height (if it's correctly set) the sensors are close to half way through the available travel as shown in my photo's. This allows max articulation in either direction.

kernowdragon · Mar 10, 2011

Thanks Datatek, but I'm still not convinced. I see from the pics the wear on the righthand track, however if the sensor is fitted in reverse, with the linkage operating through a range exactly the reverse of before, surely the armature is reading from the unworn lefthand track?

Datatek · Mar 10, 2011

kernowdragon said:
Thanks Datatek, but I'm still not convinced. I see from the pics the wear on the righthand track, however if the sensor is fitted in reverse, with the linkage operating through a range exactly the reverse of before, surely the armature is reading from the unworn lefthand track?

Look more closely. This is not a normal potentiometer, one track is a potential divider in series with the other track so a combination of both tracks are used to produce the output for the ECU. That is why it is not easy to produce a low cost replica which was my original intention. The wear on both tracks was much the same but it does not show up that well in the photo.
Anyhow, it's your choice and your risk. Personally I prefer to fix things rather than gamble on a problem away from home.

Sorry - Yet another EAS question!

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