Height Sensor Readings and Calibration

Hi All,

Just changed the FL height sensor on my 2000 4.6.

I understand that from 97MY on they can be swapped from side to side, but I'm struggling to calibrate it due to some dodgy readings.

I have blocks for standard height, so she's currently sitting on those (double checked with Saint's height diagram ).

Most of the sensors are reading around 115, but the new one is reading 40. When I first put it on at high height, it was reading 20 with the others reading 150ish.

I initially assumed this was because it was on 'upside down', but can't get it to take those readings at all. A search on here threw up acceptable limits down to 50ish.

So, what have I done?

Also, if anyone can shed some light on the correct calibration procedure using a faultmate (with vehicle explorer software). At the moment, I'm saving the current settings, editing the html file it save, and trying to reload it before 'write settings'. Obviously the problem I've got with the sensor reading isn't helping this work too well, but am I trying to calibrate it correctly doing this?

Cheers
Marc

OK, just gone to put the old one back on so I can drive her tomorrow, but that's now only reading 5!

Gonna go check the tyre pressures on the bike for tomorrow then!!

Any ideas?

Assume it is a new sensor!

Thought the swappable ones were 1999 onwards but could be wrong...still, should be correct for your 2000 model...

I trust you have mounted it all correctly and the link arms are correctly positioned...

If you can disconnect it and using a DVM measure the Resistance reading, and then move the arm up and down and see if the Resistance changes smoothly with no jumping around.

It could also be dodgy wiring to/from the connector giving dodgy resistance values...

Yep, new sensor, dunlop in a LR box no less (from the bay tho!!!).

Rave gives differing instructions for swapping from 97MY, so it is an assumption that its 97.

It's the mounting it correctly I'm not 100% sure of. Purely because the readings seem 'upside down', i.e the value went up dropping from high to standard.

The arm only seems to have 180deg of travel, whereas the old one seems to have 360.

It should only have 180 travel on the lever, if you try and spin it round 360 you snap the sensor inside, then its scrap, you're-sensor is probably fine, just a bad connection or incorrectly installed. I maybe wrong though!

kurtjohnson10 said:

It should only have 180 travel on the lever, if you try and spin it round 360 you snap the sensor inside, then its scrap, you're-sensor is probably fine, just a bad connection or incorrectly installed. I maybe wrong though!

Click to expand...

Pleased I didn't try to encourage it then

I presume there's no way of disconnecting the arm from the sensor and kinda turning it over, it feels like it should be on the other end of the travel to get higher reading, if you see what I mean.

That said, I've changed it because I was getting an out of range error, intermittantly, which I put down to knackered sensor but it could be connections to it.

It does sound like a corroded or loose connection to me, especially when you said you put the old one back on and the reading were low.
Give the socket on the lead a clean then check you haven't bent one of the pins in the h-sensor when fitting the lead to it.

Will do. stuck at work for the day now tho, so will be this evening before I get to it

Do they not work with high readings at one end of the movement, and low at the other? I'm assuming they do, hence the feeling that it's upside down. This may be an incorrect assumption!!

You aren't by any chance trying to fit a rear sensor on the front are you.

The sensor is just a rather complicated potentiometer, it does not have a high end or a low end, the reading from the wiper contact to either outer contact will give the same values over the travel, one going high and the other low and vice versa depending which way you move the arm.
The arm should move no more than 180 degrees, and more any it's fecked.
Either the new sensor is duff, coming from fleabay that's a good possibility, the box means nothing, or there is a bad connection.
The RSW software is easier to use than Faultmate for calibration.

+1 on the RSW software. It's easier to use/calibrate and it will give repeated error messages if you've got a duff sensor. You can have a trip along the coast to Hastings if you need to borrow mine, but would probably be cheaper than the petrol to get the lead/software from datatek.

Cheers guys.

I had thought about whether it was a front one, but the pics all look to be correct against rave. The only thing different is that the multiplug goes directly into the sensor on the new one where the old one had a fly lead off it (into the multiplug). I'm hoping that's just a change to design, rather than wrong fitment.

I'll try putting the DVM on in this evening as per Ant's suggestion, which will hopefully at least show if I'm flogging a dead sensor, then make sure all is fully cleaned up at the multiplug.

As it's FL it should be fairly easy to check continuity back to the ECU if needed too.

Thanks for the advice on the calibration, if I can't get anywhere with faultmate (I did find another site last night which walked it through, but needed height blocks for all 4 heights, although it did give the heights between axle and bump stop for each one) I'll PM datatek to get the lead and software. Cheers for the offer Kev, but agreed its probably easier to get it, and I'm sure it won't be the last time its needed!! At least at the cost it is, I won't need to go through the conversation with SWHMBO as to why the £700odd diagnostic kit won't do it

Will let you know how it goes.....

Cheers
Marc

Marc, I think the sensor you've bought is the wrong type. For your year/model the sensor should have the wires attached with a multi plug connection. The non-interchangable types have the connection on the sensor itself.
Might explain the strange readings.

kevwill said:

Marc, I think the sensor you've bought is the wrong type. For your year/model the sensor should have the wires attached with a multi plug connection. The non-interchangable types have the connection on the sensor itself.
Might explain the strange readings.

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No, the interchangeable later ones (Mid 1997 on) plug directly into the sensor. It is the early ones that have the flying lead.

wammers said:

No, the interchangeable later ones (Mid 1997 on) plug directly into the sensor. It is the early ones that have the flying lead.

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Ah, my mistake. There must have been a bit of a crossover around these years. My '98 model had/has sensors with the flying lead (non interchangeable then). Sounds like Marcs Rangey has the same.
I'm guessing you can't have the 2 different types without it confusing the eas system?

kevwill said:

Ah, my mistake. There must have been a bit of a crossover around these years. My '98 model had/has sensors with the flying lead (non interchangeable then). Sounds like Marcs Rangey has the same.
I'm guessing you can't have the 2 different types without it confusing the eas system?

Click to expand...

The ones with the flying leads are supposedly not interchangeable side to side. The ones without are supposed to be. 98 should have sensors without flying leads. To be honest have not gone into the reasons why they can't be swapped over. Earlier units are wired same front and rear. All fronts late and early are wired the same. Rear units on later versions have different pin designations. Wiper pins stay the same but power and earth are transposed on the rear units.

Interesting, it's defo one with a flying lead that has come off, but I've got a 2000 plate rangey, so shouldn't even be near a cross over.

Theoretically though, if they're wired the same, should it matter even if they are different types, could be someone has put earlier types on mine at some point (only had her a couple of years), on the correct sides, but I'm now swapping back to interchangeable ones (i.e the correct ones?).

So, does that mean I need to get another so I've got a matched set?

Just done the DVM check and all seems fine, so now to put it on the car to see what happens.......

pic of old and new.

Cleaned multiplug, still reading 42 on the standard height blocks.

Now to rave to try to work out which pins off the ECU go to FL.

Might have a quick search first to see if they can be mixed though.....

marcinbrighton said:

pic of old and new.

Cleaned multiplug, still reading 42 on the standard height blocks.

Now to rave to try to work out which pins off the ECU go to FL.

Might have a quick search first to see if they can be mixed though.....

Click to expand...

Something odd about your car, the sensors should not have flying leads if it's a year 2000. Hope it's not a cut & shut job.

Datatek said:

Something odd about your car, the sensors should not have flying leads if it's a year 2000. Hope it's not a cut & shut job.

Click to expand...

Me too.

No obvious signs, and never been a problem with the chassis no. when I've had to get parts from the stealers. V5 all present and (seemingly) correct.

Any other way I can check?