MFD stopped working after catalytic converters shield installed

I installed a hybrid battery in a Prius once that had this same reaction... The failed MFD is a known problem due to a failed capacitor on its circuit board and not related to any other vehicle failure, though electronics can make it seem that way at times.

First, make sure it's not just the dimmer switch on your dash lights...

Then, if you or a friend are DIY and can take apart your dash and replace the capacitor on the board the cost of repair is the cost of the capacitor. But if you want a shop to do it things can get expensive. Also Texas Prius Battery Replacement does this service via mail if you can remove the MFD and ship it to them.

 

sometimes, reconnection of power can send a weak electrical component over the edge

 

The MFD is the display in the middle of the car, where you get your radio and AC information. The thing that fails on the Prius is actually called the Combination Meter

 

yep... anything that slightly alters the flow of electrons once that flow is at the point of failure inside the component... Kinda like cookies... You don't think they're gonna crumble but then next thing you know...

 

Don't know where you live it, but it has been awfully hot in the San Gabriel valley for the last couple of months. All that heat may have baked the key capacitor just a bit too much for it to still function.

 

Yes MFD starts out as an intermittent problem... And sounds like your 12v just needs a decent overnight charging with a competent 12v charger. Don't waste your time on cheap trickle chargers, you need some solid amp pumped into your 12v to bring it back to normal if its still capable of that.

 

Very interesting. I took four years of electronics so if the capacitor is generally the culprit I'm game to try. Is there an online explanation of where to find it and what cap I need to buy? Much appreciated.

 

There is a very informative thread pinned to the top of this forum

Combination Meter Repair - DIY

You might want to skip to about halfway down page 12 ff after reading the first two or three pages. There again you might enjoy reading the entire thread.

 

Looked through there. Doesn’t seem to be much about the mfd though. Am I in the wrong place?

 

All the cross-talk confusing the MFD with the CM. Sorry.

 

Try this?

Prius Maintenance and Dash Problem Solved – Gen 2 Do-It-Yourself Solution for Dash


2nd Generation 2004 2005 2006 2007 2008 2009 Toyota Prius Speedometer Dash Light Out Issue Complete Fix DIY
How to completely fix outage/dark cluster, combination meter, instrument panel, speedometer, or dash on a 2004 2005 2006 2007 2008 or 2009 Toyota Prius
To completely fix your cluster, combination meter, instrument panel, speedometer, or dash that is going out and causing other issues such as not being able to turn off vehicle, unable to open trunk, backup camera not functioning, and forcing you to reset your Prius by unplugging the white harness by the battery terminal, which will only solve the issue temporary; follow the next steps to fix it completely and avoid paying hundreds of dollars for a simple solution. Do-it-yourself!

Heads up! You will need to remove dash and solder a capacitor in back of the speedometer, which should be a piece of cake if you follow the steps below.

Estimated time to complete the job is 1.5 to 3 hours, but make sure to take your time so you won’t break any pieces.

 

Ooops. Posted wrong one.
Here’s the MFD link I was thinking of.

Prius 2nd Gen - Repairing the Multi-function Display

 

same thing is true in politics