Engine light mystery

[OutlawS3]

Ok guys I got a goood one for you.

I'm having porblems with my engine light coming on after I fill up. I ride it for 75 miles and the light goes out until I refill the tank. The gas dumby light works fine, comes on around 150 miles and goes back out after fill up.

I've had my local dealer check it and it registers some sort of gas sending unit malfuction. They reset it and it was fine until I filled back up.


Any ideas? Forgot to mention it's an 04

[DEcosse]

Sure sounds like you have a bad sender unit.
Try this - get a 47ohm resistor from Radio Shack, unplug the sender and stick one lead of each end of the resistor into the harness connector (the end going back into the bike harness, not the one to the sender).
Make sure it is jammed in there pretty good making tight connection to each pin of the connector plug (fold over the leads to increase the interference fit) & tape it up temporarily.
If your problem goes away then you can prove it's a bad sender for under a dollar rather than having to buy a new sender immediately.
Be careful to log your mileage so you can tell when you need to refill while it's in that temporary condition!
Also, you may need 3 warm-up cycles to clear the initial error before a valid test can be performed.

[Gdsila]

This sounds like the common fault on the 02-04 S3's if you overfill the tank (up to the black plastic filler neck) then the check engine light comes on shortly thereafter. It will take 3 heat cycles ie: stone cold to fully warm 3x for the fault to clear the ECM and the check engine light to go off.
Happens to my 03 all the time.