computer resets at startup
10-31-2007, 06:11 AM
#1
Pro
Thread Starter
computer resets at startup
(this is an 89 S4)
okay, i have got my starting and idle trouble fixed, and now everything works very well.
Except this small thing. When i turn the igniton on the dash lights up fine. But when i start to crank, the display in the dash goes pixel crazy. When the engine then fires, it says Type 00 ect. ect. and then back to normal behaviour.
This means i guess that the computer has taken a reset. The avg consumption have reset and so on.
Is this because of bad battery? or what can it be?
(the voltmeter shows fine between 13-14 while driving)
thanks for any advice!
okay, i have got my starting and idle trouble fixed, and now everything works very well.
Except this small thing. When i turn the igniton on the dash lights up fine. But when i start to crank, the display in the dash goes pixel crazy. When the engine then fires, it says Type 00 ect. ect. and then back to normal behaviour.
This means i guess that the computer has taken a reset. The avg consumption have reset and so on.
Is this because of bad battery? or what can it be?
(the voltmeter shows fine between 13-14 while driving)
thanks for any advice!
10-31-2007, 06:39 AM
#2
Cottage Industry Sponsor
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This is a clear sign that either of the following is the case:
1. Your battery is weak and going bad, or
2. You have some kind of an electrical connection problem - typically a ground connection. Check the strap from battery to body, and the strap from body to the engine first.
But I would think it's most likely the battery; probably a bad cell. That's what I have experienced twice, with the same symptoms.
What does the Volt Meter show when you turn on the ignition without running the engine? Anything less than 12V?
1. Your battery is weak and going bad, or
2. You have some kind of an electrical connection problem - typically a ground connection. Check the strap from battery to body, and the strap from body to the engine first.
But I would think it's most likely the battery; probably a bad cell. That's what I have experienced twice, with the same symptoms.
What does the Volt Meter show when you turn on the ignition without running the engine? Anything less than 12V?
10-31-2007, 06:48 AM
#3
Paalw,
I have checked in the 'Diagnosis of the Instrument Cluster' for the 1989 S4 and I cannot locateType 00 error.
As a guess it may indicate that the battery voltage, whilst cranking the engine, is too low which is causing the problem you describe.
As an initial check, you can attach a Digital Multimeter, setting on volts, across the battery terminals and start the engine and get someone to check the voltage under starting load. If the voltage is too low (I don't know the exact low voltage that maybe causing your problem.
As a definative test I would suggest that you have your battery checked at its rated CCA (Cold Cranking Amphere) load and check the resultant voltage.
I recommend that this CCA test be done by a competent technician (not a salesman)before investing in a new battery. A load equal to the CCA for a specific time will give a resultant voltage reading under its design load conditions.
If the voltage drop is more excessive than with the DMM then this will most probably be the reason for the effect you describe to your electronic instrument cluster, that is the battery is no good.
Tails 1990 928 S4 auto
I have checked in the 'Diagnosis of the Instrument Cluster' for the 1989 S4 and I cannot locateType 00 error.
As a guess it may indicate that the battery voltage, whilst cranking the engine, is too low which is causing the problem you describe.
As an initial check, you can attach a Digital Multimeter, setting on volts, across the battery terminals and start the engine and get someone to check the voltage under starting load. If the voltage is too low (I don't know the exact low voltage that maybe causing your problem.
As a definative test I would suggest that you have your battery checked at its rated CCA (Cold Cranking Amphere) load and check the resultant voltage.
I recommend that this CCA test be done by a competent technician (not a salesman)before investing in a new battery. A load equal to the CCA for a specific time will give a resultant voltage reading under its design load conditions.
If the voltage drop is more excessive than with the DMM then this will most probably be the reason for the effect you describe to your electronic instrument cluster, that is the battery is no good.
Tails 1990 928 S4 auto
10-31-2007, 12:52 PM
#5
Chronic Tool Dropper
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Replace the battery. Do it now, before the extra load decides to chew up alternator life.
You can do a test of battery condition using an inexpensive tester available at any decent parts store. tests the specific gravity of the fluid in thecells, which indicates the relative health of the battery. Cheap floating-ball testers are a buck or two. Should be part of the annual electrical ritual anyway, so buy the tester and keep it in your home toolbox (in a plastic bag...).
Meanwhile, the low voltage on cranking is causing the dash computer to reset. The display flashes the firmware code when it resets, including the date it was issued. Mine comes up with a 1988 date, for instance. A new battery wil cure the problem.
There are lots of opinions on 'best battery'. On the advice of the list here, I bought a Duralast at Autozone. It's the same battery that Interstate offers but for a lot less $$. Good warranty and lots of stores to honor it. Been in the car for several years now with no problems.
You can do a test of battery condition using an inexpensive tester available at any decent parts store. tests the specific gravity of the fluid in thecells, which indicates the relative health of the battery. Cheap floating-ball testers are a buck or two. Should be part of the annual electrical ritual anyway, so buy the tester and keep it in your home toolbox (in a plastic bag...).
Meanwhile, the low voltage on cranking is causing the dash computer to reset. The display flashes the firmware code when it resets, including the date it was issued. Mine comes up with a 1988 date, for instance. A new battery wil cure the problem.
There are lots of opinions on 'best battery'. On the advice of the list here, I bought a Duralast at Autozone. It's the same battery that Interstate offers but for a lot less $$. Good warranty and lots of stores to honor it. Been in the car for several years now with no problems.
11-06-2007, 03:11 AM
#6
Pro
Thread Starter
ok thanks for the replies
got myself a new battery. Everything works fine now.
Opened the old one and there was no water at all in the cells. I filled it with water and will try to charge it. If it works ill use it in another not that power demanding car.
got myself a new battery. Everything works fine now.
Opened the old one and there was no water at all in the cells. I filled it with water and will try to charge it. If it works ill use it in another not that power demanding car.
