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Old 01-27-2005, 09:11 PM
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JimF JimF is offline
'94 S500: only 793 sold!
 
Join Date: Mar 2001
Location: San Diego, CA
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From what I've personally . . .

Quote:
Originally Posted by 400E
I was unclear in my question. Here's what I meant to say:

How long do fault codes stay in the computer if they are not manually cleared?

I had understood that the computer itself has the capacity to clear certain codes if a certain number of normal operation cycles (i.e., engine start/stop) occur, so that a one-time, transient fault code won't stay resident in the computer forever.

Is this accurate?
seen, anytime there's a "light", there's a "code"! And you are correct, some codes take a number of occurances to cause a light and a certain number of "trips" to clear. The definition of "trips" has changed as the models change but it's not just engine starts and stops but involves engine rpm and length of time.

On the other hand "running" problems can instantly light the CEL but do take time (# of trips) to clear. For the DI module it takes eight (8) events to trip a CEL.

For this module a “TRIP” is defined as:
1) Engine running for 5 minutes or more,
2) Tachometer greater than 700 rpm,
3) Speedometer greater than 2.5 mph,
4) Engine shut off for 30 seconds or longer.

Can't see how an ASR problem would not generate a code or two. There's a code for the brake lamp switch as you probably know.
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Last edited by JimF; 01-28-2005 at 03:30 AM.
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