MFD Screen issues-- 'Check Air Conditioner connection'? No consumption screen?

In case you didn't see this:
Prius MFD
It explains one failure mode for these, with symptoms like yours. It's a bit of an odyssey getting to it, but it can be replaced by the DIYer.

There are a number of places with salvage units available now that Prii are getting in wrecks, i.e. AutoBeYours.com. Much less $ than what you were seeing for new ones. Others on PC here will chime in as well.

The main functioning of the drive train is not controlled by the MFD, so the car can carry on without problem.

 

Seeing you noted a 2004 Prius, what is the condition of your +12 volt battery. When the 12 v battery heads south, goofy things happen. Do a battery test, and if you are sitting under 11 volts, time for a new battery, I would recommend an Optima!

 

Your first respondent pointed you in the correct direction. I followed the Hobbit's direction and repaired my own MFD. If you feel uncertain of your skills, contact Plug In Hybrid Electric Vehicle PHEV . Steve at AutoBeYours will offer you a solution for under $400.

JeffD

 

I replaced the 12 v battery in my 2004 prius with the Optima battery from elearnaid. The voltage was improved, read above 12.0 at all times in acc mode, and 14.0 with engine on. But, MFD gives reading "check the connection to air conditioner". Is this a battery problem? I took it to an a/c shop, they checked all of the connections and they think it's the MFD problem, but the a/c was working perfectly with the old battery until i installed the new one. I then reinstallled the old battery, in case the Optima battery is defective, but MFD reads the same. Did I blow out the MFD when I changed batteries, or is there a reset or reprogramming that is necessary for the ac? I would appreciate any help with this frustrating problem, esp with the outside temperature here in Florida close to 90 every day. Thanks

 

This sounds like the classic 2004-2006 MFD problem. See: Prius MFD. Steve at Prius hybrids sales and service Scottsburg Indiana repairs MFDs for $325 plus one way shipping.

JeffD

 

No, I don't believe so.

If you mean blow up the MFD (as in destroy it) when you say blow out the MFD then no, I don't believe there is any co-relation of one to the other.

Did you even read nh70's post #2 and the link therein that pointed to Hobbits article? I believe this contains all the answers to your questions. Jeff's post #4 may be more applicable to your capabilities.

 

I just posted today about the same problem (no AC or powetrain/battery readings on the MFD) but on a 2007 Prius (so not the 2004 - 05 problem described here). Steering wheel controls work fine for the AC still.

The problem appeared during a shop's installation of an afternarket radio. The tech screwed out the MFD and left it dangling there and I suspect that he may have twisted a connection or something. Short of buying and installing another MFD what can I get the shop to do to try to fix this? I suppose I can check the connections going into the MFD... Is there a specific pin I should lookout for? Or is the problem likely to be on the circuitboard?

 

When you install an after market radio, you need to install a 68 ohm resistor between two terminals or you will get this error message. see: https://priuschat.com/threads/2005-prius-aftermarket-stereo-install-pdf.49438/

JeffD

 

Forgot to mention, this solved the problem! The tech had forgotten to install the resistor. Thank you!!!!

 

Crossposting this thread for anyone that was searching for a solution which can be found in the link here: https://priuschat.com/threads/2005-prius-aftermarket-stereo-install-pdf.49438

Thank you F8L!