Amateur MFD Repair Adventure... and advice!

Hello All,

I am a brand new member and this is my first post to PriusChat. Let me introduce myself as someone who is a bit of a control freak when it comes to car repair and my experience with car repair mainly deals with late models of yester-year. Basically, if it doesn't have a hybrid system and isn't fancy, I know how to troubleshoot it.

However, I recently purchased a used Gen. 2 Prius touring with Navigation as a college graduation gift after previously having driven an '03 Mercury Grand Marquis LS and an '88 Toyota Corolla (carburetor, California smog...so many vacuum tubes) before that.

Now on to the MFD debacle:

The MFD display would only register my touch on the right quarter of the screen no matter where in the other 3/4 of the screen I would touch. Otherwise the display changed when I pressed buttons and reacted with no delay at all. I thought this to be a good sign because hopefully there was an issue with the connection of the digitizer to the board and simply unplugging and re-plugging in that connection would hopefully solve the issue.

In the mean time, I had gone to a Toyota Dealership to get the part number of the MFD and they reported back it would be 86110-47071 and I ordered one on eBay for a relatively cheap $176 compared to the dealer's quote of $9,700. The eBay MFD came and I waited until I would extract my own to see if this one would work and I could be free of the need to disassemble my own MFD.

*The eBay MFD came slightly damaged and I was given a complete refund. It was now mine for any salvageable purpose*

Cut to 2 weeks later, I decide to extract the whole assembly to see if the good old "Unplug and Replug" will sort things out with the touch screen It does not. Model of MFD acquired: 86110-47220. The eBay one will not work because it was purchased with an incorrectly given part number (the 86110-47071 is the incorrect part number).

From here on out, the incorrect MFD will be called "MFD1" and the correct one will be called "MFD2"

Anyway, with half of my dash disassembled, I continued to drive around for the next week contemplating my next move.

I decided that I would extract the display assembly from MFD1 and put it into MFD2. This was not possible because the cables are in very different positions. I then decided that I would at least plug in MFD1 to confirm that works even though it won't fit my Prius. I plug it in and the screen remains black and the airbag (SRS) light is permanently illuminated. What. The. Hell.

Being scared that I have royally screwed something up in my car, I plug in MFD2 to see if it still powers on. It does not! MFD2's screen is black and it is not responsive at all. This is where things get weird. Somehow in fiddling with the MFD of my car, I have managed to disable the airbag (SRS) system?!

Just today, I brought the car down to my local mechanic and he told me there are B1650 and B1794 codes on the car. He is fixing them and I'm going to just by another working MFD for my car on eBay.

TL;DR
Advice: Don't plug in MFDs that aren't exactly the model of the one you pulled out of the car.
Has anyone experienced SRS faults when replacing the MFD? Also, does anyone know if alldatadiy has comprehensive electrical diagrams for the MFD harness cables?

 

Yeah, I currently have a subscription that lasts until tomorrow with toyotatechinfo but it's like pulling teeth trying to navigate it and cull information for later use. If only I had done this 4 months ago when I still had a few thousand pages worth of printing credits at my university. I'm tempted to cough up the $50 and get an alldatadiy 5-year subscription because it seems like they have just as much info as the toyotatech. As for the wiring diagram, I'll look into getting one on eBay as you suggest.

Also, what's the SRS "nag" you speak of?

The repair guy came back with B1650 (Occupant Classification System Malfunction), and B1794 (Occupation Classification Battery Positive Line Malfunction). At first, my scan tool only detected the B1650 which only requires a reset of the sensor that detects someone sitting in the passenger seat. Unfortunately, I don't have a SnapOn scan tool with BCM capabilities so I missed the B1794 code. Already $230 in the hole for the diagnosis... will report with the total when I get a call later today.

 

I love fixing traditional cars, but man, this hybrid technology will be a huge learning curve! I'll have an electrician's tool box by the time I let go of this car.