Height sensor testing

mikeateves · Apr 3, 2013

Hi,

I think I need to test the height sensors on my '96 P38a which I was going to do by measuring the resistance as the arm moves. Is it sufficient to just disable the suspension by leaving a door open or do I need to do more e.g. disconnect the battery before disconnecting and removing the height sensors?

Thanks,
mikeateves

Saint.V8 · Apr 3, 2013

Engine off, door open, remove delay timer and with luck the ECU will not know what is going on when you disconnect it!...

Safe side is to disconnect the battery!

mikeateves · Apr 3, 2013

Hi Saint.V8,
Thanks for the reply. It's easy enough to disconnect the battery so I'll go for that.
Mike

TCubed · Apr 3, 2013

mikeateves said:
Hi Saint.V8,
Thanks for the reply. It's easy enough to disconnect the battery so I'll go for that.
Mike

It's the reconnection that's fun....

sandyt · Apr 3, 2013

mikeateves said:
Hi Saint.V8,
Thanks for the reply. It's easy enough to disconnect the battery so I'll go for that.
Mike

If you disconnect the battery you may get locked out and have to put the code in I have found putting key in ignition band leaving in has helped

Datatek · Apr 3, 2013

mikeateves said:
Hi Saint.V8,
Thanks for the reply. It's easy enough to disconnect the battery so I'll go for that.
Mike

Absolutely no need to diss the battery or remove the relay as long as you leave a door open.
Very difficult to do a meaningful test with a DVM, you really need to put a low voltage on it and look at the output with a scope to see the sort of rubbish that upsets the system.
The easiest way to know you have a duff sensor is when it consistently flags the same sensor fault on diagnostics.

Saint.V8 · Apr 4, 2013

Datatek said:
Absolutely no need to diss the battery or remove the relay as long as you leave a door open.
Very difficult to do a meaningful test with a DVM, you really need to put a low voltage on it and look at the output with a scope to see the sort of rubbish that upsets the system.
The easiest way to know you have a duff sensor is when it consistently flags the same sensor fault on diagnostics.

My thoughts were although the ignition is off, the EAS ECU does wake every X hours to check heights, even though a door is open I thought the ECU would still check the sensor readings, it just won't do the height change....

So leaving a door open pauses the height check time delay too??

TCubed · Apr 4, 2013

Saint.V8 said:
My thoughts were although the ignition is off, the EAS ECU does wake every X hours to check heights, even though a door is open I thought the ECU would still check the sensor readings, it just won't do the height change....

So leaving a door open pauses the height check time delay too??

I think having a door open freezes the whole ECU

Datatek · Apr 4, 2013

TCubed said:
I think having a door open freezes the whole ECU

As above.

Height sensor testing

mikeateves

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Saint.V8

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mikeateves

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TCubed

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sandyt

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Datatek

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Saint.V8

Dyed-in-the-wool 100% RR Junkie

TCubed

Active Member

Datatek

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