200 Avant (1B) oil warning

[steveb]

'89 200 avant with an autocheck, she keeps alarming for oil level or is it pressure ? high and low alarms it even alarms when the engine is not running this is the red oil can flashing on the autocheck does anyone have any info. on how the system works ? I have changed both switches and it has made no difference The pressure gauge says all is ok

[Woodsman]

Steve,

On my 200, 1984 KG I had a similar problem, like you I changed both switches and still no different

I tried to test the switches and came to the conclusion that the old and new 1.8 bar switches were buggered

Once again I was wrong, It turns out that the 0.5 bar (white IIRC) is a normally closed (NC) type (ie contacts are closed, then open when the switch sees pressure) and the brown 1.8 bar switch is a normally open (NO) type

The problem was that the previous owner had put the wires round the wrong way.

The garage I do some work for had same prob on a late wasserboxer campervan a couple of weeks ago, I must admit I saw the boss change both switches, then watched him scratch his head for 2 hours before I told him

Try swapping the wires, hope this helps

Peter

[5potnoodle]

Hi Steve,
Have a look on my (sadly neglected) site www.audi200.org.uk and go to the technical area. There you will find a pdf relating to fault finding of the autocheck system.

Dry solder joints on the instrument cluster printed circuit board are the usual culprits (btdt) but worth going through the correct procedure if you can to establish the course of action.

Other than the aforementioned possible causes, I'd also say that audi wiring has a tendency for the outer wire sleeve to go brittle and crack, allowing moisture in and corrosion of the copper strand inside, or even just too much verdigris on the connectors at the pressure switches where they are crimped onto the wire.

Hope that helps.