Help on 'False Computer Warnings'

theo · 11. Januar 2005

My 94 840 is playing with me!

The 'check' function on the computer is telling me that I have '1. brake lamp failure' now 2 days hence it also tells me I have a 'low beam failure'.

A couple of weeks back it sent a high temp reading (almost into the panic area) to the guage while simultaneously sending a computer message reading 'check owners manual' ( a better message might have been 'do not drive further, pull over, switch off and get a tow'). It normalised after two ignition close downs.

Something is amiss and I have no idea where to begin. Any suggestions from any one please?

Thanks and happy 2005
Theo

nzmoko · 11. Januar 2005

Batteries...

Hi Theo,

I had a similar problem with Low Beam Failure (even though my low beams were fine). I traced the problem to an aftermarket low beam bulb. Replaced both with H1 from BMW (about 3 dollars each). Replaced both and problem never came back.

Also, dying batteries can also throw up 'errors'.

Have your batteries Load Tested by your mechanic (some of those auto places like Bob Janes might do the Load Test) and if they fail, replace both.
If the batteries pass the Load Test, recharge them and they should be ok and may just stop your MID spitting out errors.

ps. If you don't drive your car much, maybe think about investing in a BatteryTender (.com) to keep the batteries healthy.

shiggsy · 11. Januar 2005

Screwy electrics warnings, especially the false bulb warning messages are usually an indication that your batteries are knackered. I haven't heard about them giving the other problems though.

theo · 11. Januar 2005

Thanks guys,

keep the suggestions rolling. My batteries are not yet 12 months old but I will look at the connectors on the brake bulbs. Perhaps there could be a resistance type problem there. As for the low beams? Its an intermitant so far did it twice while the brake fail seems permanent.

Cheers
Theo

nzmoko · 11. Januar 2005

Try replacing the low beam bulbs. The cheap ones caused me the same intermittent problems.

TerryY · 12. Januar 2005

Hi Theo
I got the brake light warning and 2 days later one of the bulbs actually failed!

Do you have the high brake light there? Many here keep fooling with the lower brakelights and then finally realize that there is one up high

Have you changed either a brake light bulb or headlight recently? Mismatched bulb bases(different brands) seem to trip the warning too.

The test is a simple comparative resistance test of each loop with a bulb in it but it could also point to the ground side of the wiring for the bulb.

Have fun!!

theo · 15. Januar 2005

Would someone please tell me what a knucklehead I really am because I have forgotten just how dumb I can be.

The upper brake lamp on the parcel shelf is also wired in to the system and actually also sends a message when it dies.

I guess my excuse could be that in addition the computer had picked up what may be a resistance problem on low beams. It's gone for now but 'll know where to look if it comes back. Had the problem b4 and it was a crappy globe.

Had my first drive in an 850 yesterday. Impressed with the sooooooth torque. Thanks for the drive Ralph!

Peter West · 15. Januar 2005

I've had these lamp warnings too, in my case on Fog lights when the fog lights weren't on. Recharging the battery seems to have fixed the problem.

I had the problem on the rear number plate light a few days ago, today the bulb blew. Perhaps the system can sense a malfunction before it actually blows in some cases.

I'm having problems on brake linings now, but I think the new pads fitted recently may not have had the connection into the computer fitted correctly.

Also (God, I didn't realise how much problem i was having) windscreen washer level warning wouldn't go off at one time, replacing the sensor fixed it (about £18 GBP)

Peter

theo · 16. Januar 2005

thanks Peter for the input.

You may be interested to know that you can by pass the brake pad sensors so that they are not operational at all. Means you get 25% more use out of your pads. Just need to keep an eye on them the way 90% of other cars on the road need. Its a personal choice but for me the wheels are off for regualr cleaning so I check them while cleaning.

regard, Theo

Help on 'False Computer Warnings'

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