Not charging, no "plugged in" light on dashboard

[nico]

Coming back from an event-free ride, when I plugged in my 2012 Miev in a 220vac charger nothing happened. The dashboard light confirming that it is plugged in did not come on and the car did not charge. I also tried with two 120vac chargers with the same results. (My other Miev charges OK with all those chargers).

The on-board charger has been replaced under warranty last year and I tested another cable from the side connector to the on-board charger: same behavior. The 12 volt battery has been replaced last year. The car runs correctly as I was able to drive to the dealer with only two bars remaining.

With Canion, I was able to connect and read the voltages of the battery cells (only 2 out of 16 bars left, high=3.765V, low 3.735V, avg 3.750V, 330V, SoC% 22.0, the main battery is approximately 70000km, the car is 172000km).

The dealer has tested the on-board charger and followed the testing procedures and found nothing wrong anywhere. There were not fault codes. I asked them to clean the ECU and BMU connectors and check the on-board charger and EV control relays: everything looks ok. They asked for remote support from Mitsubishi tech support in Canada and did a remote troubleshooting session with them. Their conclusion is that it is "probably" the BMU but they will not commit themselves to anything. They say a replacement BMU (CAD1200$+labour+taxes) has to be VIN programmed to be installed in my car; if this does not work, I might be wasting money for nothing.

By coincidence, the dealer has another 2012 with the exact same problem. He has been searching for a month and also concluded that the BMU must be replaced to continue the troubleshooting. Without being 100% sure the BMU is bad.

It simply looks like the car never detects the ac is plugged in.

-Does anyone have any hints whether the BMU replacement would resolve this issue?
-If it does not, what are the other possible culprits? If they don't need to be VIN programmed, I could try to swap them from another Miev... But if they all are very expensive, I will probably just abandon the car (A working 2012 Miev with 60000km sells for CAD6000$ these days...).
-Can the identification chip be moved from my possibly defective BMU to another BMU previously used in another 2012 Miev?
-What else could I ask the dealer to check?

Thanks for any help!

 

[kiev]

Would you use a voltmeter to measure the 12V aux battery voltage with key OFF, with key at ACC and ON, and after start to READY? measure at the battery terminals under the hood.

 

[nico]

It will be done Monday.

 

[PV1]

What is the condition of the car’s J1772 connector? What about the cables connecting it to the on-board charger?

With a charge cable plugged into the car, will it go READY?

 

[nico]

I had a spare cable with a pre-assembled J1772 connector at one end and some pre-assembled connectors at the other end (one of which connects to the on-board charger’s input). I used it to bypass the car’s j1772 connector and the cable that feeds the on-board charger. This cable was from another 2012 Miev. The car would still not detect that a power source was connected, essentially ruling out that cable the the j1772 connector as the problem.

When no power source is connected to the j1772 connector, the car starts and runs normally.

The car is at the dealer’s. Monday, I will check if the car will start with a power source connected to the j1772 connector. It normally should not.

 

[nico]

12V Battery voltage with ignition key at:
Off: 12.1 volts
Acc: 11.8 volts
Ready: 14.5 volts

I have yet to confirm if the car starts with a charger connected to the J1772 connector.

 

[kiev]

12V Battery voltage with ignition key at:
Off: 12.1 volts
Acc: 11.8 volts
Ready: 14.5 volts

I have yet to confirm if the car starts with a charger connected to the J1772 connector.

So the DC/DC converter is working as seen by the 14.5V in READY.

The OFF and ACC voltages are much too low and indicate a weak, worn out or damaged aux battery; it might be possible to recover with a good external charging. Low aux voltage can cause a multitude of faults on the car.

 

[nico]

The dealer has tried to start the car with a charger connected to the J1772 port. He said that the car does not start. This would suggest that the wiring from the J1772 port is correct since it does detect a connected charger.

Because of the weak battery, he also connected a booster battery to bring the 12V battery to 14.3 volts. He then connected a charger to the J1772 port but the main battery did not charge. He said that the "plugged in" light now turned on. He also said that he heard two beep. This is strange because my other (working) Miev does not beep when a charger is connected and we try to start it. It could be that he heard the two beeps when the outside temperature is below 3 Celcius. Could there be a low voltage limit AND a high voltage limit on the aux battery that prevent the main battery recharge? Maybe he should have just connected a second battery to reach 12.7-12.8 volts like I suggested to him.

There is a ChadeMo recharge station about 10 kilometers from the dealer, any chance the car would charge on that charger? If it does not, I will need to have it towed...

I have access to a Miev that was abandoned because of a failed compressor. How many parts need to be "VIN programmed"? Could I use the BMU and the ECU from the other car? Are there other parts that would have to be moved along?

 

[kiev]

There is a High limit on aux voltage supply to the ECUs, i think it is about 16.8VDC in the FSM. Most external chargers don't go that high, but the high current "starter" chargers can supply 50-80 Amps and likely do go higher than 17V. i would never use a starter-charger on an EV, too many important things going on related to the 12V level to mess around and take chances, but that's just my opinion.

The fact that the red light on the dash came on during plug-in tells me that the aux was low before.
Also that the EV-ECU is working and sending messages.

Maybe all the previous issues were related to low aux voltage and it just needs a really good external charge, but the desulfation damage can never be totally repaired and is sometimes permanent.

If the car starts to READY when the aux is good, then it would likely DCQC on Chademo--that circuit is totally separate from the OBC.

 

[kiev]

It's possible, but i can't recall anyone reporting such a failure. Also to have 2 cars with this failure in the same vicinity--what a coincidence of such a rare failure mode? Makes me think there should be some DTC codes related to the BMU--my scantool will read such codes if the EV-ECU throws them up there. Plus there would be a warning light on the dash with any sort of error related to control of the HV battery pack.

Might want to Use Canion to see what your cell voltages are doing.

 

[nico]

(From first post) With Canion, I was able to connect and read the voltages of the battery cells (only 2 out of 16 bars left, high=3.765V, low 3.735V, avg 3.750V, 330V, SoC% 22.0, the main battery is approximately 70000km, the car is 172000km).

I will try to drive to the Chademo charger and see if it works. Then, I will swap the aux battery with my other miev and see if I can charge it with a level 1 or 2 charger.

The other customer has stopped all investigative work on his Miev. This week, he must decide if he sends it to scrap...

 

[nico]

The dealer's best guess was that the BMU needs to be replaced before they can continue the tests. They are not sure what the problem is but their diagnostics stop at that component. The BMU price is from CAD$800 to CAD$1200 depending on models: for mine, it is CAD$1200. I was not ready to spend that money with any guarantees it would solve the problem so I did not authorize the repair. During the discussions, I asked if I could use a salvaged BMU from another car and the dealer was told by Mitsubishi technical staff in Toronto that a BMU could be reprogrammed.

I was able to recharge to 50% at a nearby ChadeMo charger and drive home.

At home, I re-tested with a level 2 charger: the "plugged in" light does not come on.

I connected the battery of my Honda Odyssey in parallel with the 12V battery: the main battery still would not charge.

With the L2 charger still connected, if I try to start the car, the car does not start but the "plugged in" light now blinks. Leaving the key in the ACC position, if I disconnect the L2 charger, the "plugged in" light turns off and blinks again if I reconnect the L2 charger.

They good news is that the car can charge with a level 3 charger...

I had the car towed to another dealer further away: they found that one wire of the main harness from the on-board charger was damaged and that the wire had verdigris corrosion. They repaired that wire and the car is now charging again! They are running a few more tests but it looks promising. They are charging me 90 minutes of shop time, no parts. Reasonable, considering they also ran the whole set of tests...

I could have found it myself if I had looked for something like that...

I will post more once I get the car back this week.

 

[kiev]

That is great news! We have never heard of this failure--Please find out exactly which wire had the corrosion issue if possible. There are 4 possible: an AC input harness, the control harness, the 12V output wire from the DC/DC to the auxillary battery, and the High Voltage DC wires from the OBC to the MCU that then runs to the HV battery pack.