MPG doesn't work right after battery taken out.

[Nick_S]

So basically while cleaning my trunk I noticed my battery was covered in some sticky, nasty crap. Almost like molasses but kinda looked like oil. So I pulled the battery and tray and started cleaning it up.

Gross


Anyways, got that all cleaned up, battery back in. Also checked my air filter last night aswell. On my drive to work today my car was running rough, PCV hose had come off was all. But I noticed my mpg guage wasn't reading. It will read when I give it a good dose of throttle but on just normal cruising it won't read. Could I have reset something on accident? Bumped something while checking my air filter? It worked perfectly fine before so hopefully I didn't screw anything up.

Thanks
Nick

[jlevie]

That sounds like it could be bad batteries in the SI board. The batteries float on un-switched power as long as the battery is connected. But with the battery disconnected the SI board batteries are drawn down and when old they may not recover.

[Nick_S]

Ahhh gotcha. Is this the battery that is in the guage cluster itself?

[jlevie]

Yep. The SI (Service Interval) board is in the cluster and has a pair of batteries to retain data. If the batteries haven't leaked and corroded the board they can be replaced. Otherwise the whole board will need to be replaced.

[Nick_S]

I'll take a look soon. My odometer doesn't read so I'd really like to fix the gears in that and hopefully replace the battery's then too. What kind of batteries does it take? Thanks for the advice!