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8.8 MPG Since Last Reset

325 Views 7 Replies 3 Participants Last post by  cerritos
The S430 computer shows this number on the dash. Its mixed highway and surface street driving. Total miles driven 200 miles since last reset, 32 miles of freeway and 168 miles surface street driving.

Is there anything that I can do to improve this?
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2000 S430, 2000 S500, 2003 S600 TT, 2005 E320 CDI, 2006 S500 4Matic, and 2006 S350
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I've seen that kind of thing before. At your next fill-up, do it with a calculator and compare it to what the car's computer is telling you. Odds are, the car's computer is off for some reason.

How long has it been doing this, and was there any maintenance done on the car that might correlate with when this started?
 
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· Registered
1999 E320, 2001 E320, 2004 S430
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Discussion Starter · #3 ·
That's interesting. I'd never suspected that the car's computer could be wrong. I'll start to monitor the odometer readings and the amount of gas I added. Since I don't drive much on the S430, it will take a while to have a meaningful data.

The instrument cluster was replaced in March. The transmission was serviced at the same time. I wonder whether it's possible that some cluster parameter is set wrong that caused this.
 

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2000 S430, 2000 S500, 2003 S600 TT, 2005 E320 CDI, 2006 S500 4Matic, and 2006 S350
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7,724 Posts
Transmission service...that could do it. After I replaced the conductor plate on the 2003 S430, the car's computer reported incorrect MPG information for several months, in this case, about 20% too optimistic. Yep, even after resetting the "learning" in the transmission with SDS. But eventually it did go back to normal, and it was within 0.5 MPG almost every time from that point forward.
 
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