Immobile i-MiEV with RBS and Electric Motor Unit Warning Lights

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JoeS

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Hills above Silicon Valley, California
My neighbor has a 2012 i-MiEV ES with CHAdeMO. Car has 80,000 miles. 12v battery fairly new and good. The main battery is fully charged, but RR=28 at 16 bars. Haven't checked its capacity.

A very large branch fell across his driveway and he had his daughter back down to it and he hitched a rope to the branch and to his trailer hitch.

Daughter started pulling the branch up his steep driveway and as the load increased she floored it with the car and branch barely moving. She heard a click and totally lost power. They towed the car up the driveway to their home.

Car goes into READY, but shifting out of Park results in dashboard yellow "RBS" and the "yellow car symbol with exclamation point through it" which the manual calls the Electric Motor Unit warning light. The car just sits there in READY and when in gear doesn't respond to the accelerator pedal.

Troubleshooting -

My i909 shows only one DTC: C1340, Stoplight Switch Error. I can clear it, but it comes back whenever the car is in READY and shifted out of Park.

[Personal note: it makes sense as the car not seeing the brake switch closure would inhibit the car's operation when shifting out of Park. There is also a mechanical interlock which prevents shifting out of Park if the brake pedal is not depressed, and that's working ok.]

The Relay Box #8 15A fuse is good, stoplight switch itself tested good, and the brake lights work just fine. The stoplight switch wire also goes to the ASC-ECU, but no reason to suspect an open circuit there as the harness was not touched. Haven't tested for a brake light signal at Pin 30 of the ASC-ECU.

Here is what the manual says about the RBS indicator: "The indicator comes on when the regenerative brake performance may be weakened. In this case, drive the vehicle at a lower speed."

Here is what the manual says about the Electric Motor Unit warning light: "This warning light will illuminate when there is a problem with a high voltage component."

The 'click' heard at the time of failure is a mystery.

Welcome any ideas on what to do next.
 
Hi JoeS

Very strange indeed, not much to go by but maybe link below might be useful

http://mmc-manuals.ru/manuals/i-miev/online/Service_Manual/2013/35/html/M135500990012201ENG.HTM
 
Mickey S70, thank you for this. That's the diagram I started with. Interesting to see the additional information in that manual.

My next step is to positively determine that the stop light signal is getting to the ASC-ECU pin 30. The brake light switch and the brake lights are working just fine.

Love their disclaimer in the manual: "If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set."

Forgot to mention that I also tried resetting the system by disconnecting the battery for a while, to no avail.

The immobilizing of the car is certainly logical if it thinks the brake pedal is not pressed while shifting.

But what does that have to do with the car struggling very hard to drag that huge branch up the driveway just before croaking... :?:
 
JoeS said:
But what does that have to do with the car struggling very hard to drag that huge branch up the driveway just before croaking... :?:

That’s what puzzles me also, don’t believe in coincidences though, any chance some cables in close proximity’ to the tow bar got damaged?
 
MickeyS70 said:
JoeS said:
But what does that have to do with the car struggling very hard to drag that huge branch up the driveway just before croaking... :?:
That’s what puzzles me also, don’t believe in coincidences though, any chance some cables in close proximity’ to the tow bar got damaged?
Good point, as his trailer 'hitch' installation is a kluge and not a proper Torklift like I have on my i-MiEV. Added that to my list of things to look at. Thank you.
 
I still get a random pair of heavy clicks from under the dash when accelerating uphill from a stop sign. No idea what it is, but both cars have done it the entire time I’ve owned them.

Not sure what all relays are under the dash on the driver’s side, but they might be worth a check. I’d also check cell voltages with some load on them, maybe if you can coax the heater into working.
 
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