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Troubleshooting and repair for On-board Charger (OBC)

[Edit] If you have a USA car with a bad OBC, then take it to the dealer and get it replaced under the extended warranty added to cover the OBC. There was a letter sent out about this being due to faulty capacitors. Do not try to repair it or they might deny your claim. [/edit]

This thread will be used to document the technical information and any schematics or firmware available to help troubleshoot and repair the OBC/Converter. Post #2 has troubleshooting steps and an index of this thread that can hopefully be used as a guide to step through the process. Post #3 will hold a collection of circuit schematics.

There seems to be many failures reported lately (last 6 months or so), so maybe it's time to figure out what is happening and come up with a lower cost solution. i started a photo album with pictures related to this box, also all my imgur pictures are found at:

List of links to user's recent failures [and successful REPAIRS] in reverse order, later near the top:

[2020 edit to add additional repair efforts]
##. LucasH (Nov 2020). Does not chargge, but DCDC is working. LucasH

##. ZetaFunction (July 2020). Sebastian's issue with the switching power supply on the bottom board, a new issue never seen before starts here: ZetaFunction on pages 54-59 still in progress.

##. DutchLincoln (June 2020). Great pictures of disassembly to repair damaged snubbers. ... 500#p41150

[previous list]
21. 11/28/2018, Reports and more repairs by Skylogger in WA

20. PM message, 10/2018, from tdigsi; looking for substitutes to replace the 680 and 220uF capacitors?
[EDIT: REPAIRED, replaced snubber caps and MCU fuse, now it is charging; going to replace HV caps anyway due to age and high mileage, est. >~5000 Hrs on caps.]

19. PM message, 9/2018, from Quixotix in Seattle; dealer says charrger is dead; recommended to request DTCs and open cover to inspect for damage, blown fuse, etc.

18. ChristopheFR, 9/2018, 2011 C-Zero in France, EVSE charging appears to start then quits, DCDC appears to work ok, Aux battery changed in 2015

17. skylogger#2, 9/2018, 2010 in Western Australia, blown snubber caps and MCU fuse, AC relay and precharge Rs

16. footswitch, 9/2018, 2012 not charging in Portugal, EVSE charging appears to start, then just quits, DCDC appears to work ok, still running with OEM Aux battery.

15. charliejuliet, 8/2018, failed charrger in Michigan UP, replaced with aftermarket DC/DC and Chademo charrger.

14. redcane, 8/2018, 2010 not fully charging in Australia (east coast), OBC was replaced with a 2015 unit under recall in January 2017.
[EDIT: 1/8/2019,REPAIRED, replaced snubber caps and MCU fuse. Also replaced the pre-charge resistor, but that was not due to the OBC failure.]

13. skylogger, not charging in Western Australia, found blown surface mount capacitors.
[EDIT: SOLVED AND REPAIRED,8/12/2018, see picture of a twisted resistor causing open circuit on voltage monitoring]

12. beeline, 6/18, 2012 not charging, dealer estimates $4800+tax

11. mikedufty, 3/18, 2010 Australian model not charging fully in WA, charrger was replaced under recall. Dealer now pointing at EV-ECU as bad.

10. 1pk, intermittent charging level 1 and 2, found cracked bypass resistors at AC relay

9. Lic, 4/18, getting condenser timeout error P1A15, no main(+) contactor indication

8. jray3, 6/18, Mr. Bean dc converter not working, blown 20A fuse in the inverter

7. luvmymiev, 6/18, Category: i'll take bad charrgers for $4000--The question is:What did the dealer find?

6. electronpusher, 6/18, car not charging in New South Wales, blown snubber capacitors in the potted doghouse and fuse in the MCU.
[EDIT 10/7/2018: REPAIRED , replaced snubber caps and fuse and now it's working again, Good Job!]

5. Antaris, 3/18, service manager says the on board charging unit has failed.
[EDIT: REPLACED, Mits Canada replaced it for $800 Cdn]

4. fresnomiev, 3/16, dealer replaced charrger while troubleshooting by parts swapping, issue was MCU inverter.

3. pluto, 2/18, code 39 OBC, abnormal PFC voltage,

2. Sbess, 10/17,dealer says bad charrger

1. TorranceMiEV, not charging

iDriver, Nov 28, 2017, charrger fuse in MCU blown

Just for the historical record, mccluer had a very early report of charrger failure back in 2012

also DonDakin in 2013

also Malm, 3/2016

[edit: add a section of pictures of various items frequently referenced]

This shows the OBC on the left with the cover off, and the MCU on the right with the access cover open:
MCU with cover open

Here is an OBC picture with the cover open, note scorch marks on inside cover and the full exposure of the tops of the electrolytic capacitors (credit to coulomb for pointing out this indicator of high temperatures):
2015 version

EMI Filter DogHouse (External Box on some versions)

DCDC Converter Board in the bottom plenum from this post, ... =20#p36638

Flat Ribbon Cable connects between the top and bottom board

Bottom Board "DogHouse"--the fenced-in potted area.

Side view of the bottom board and waffle plate.

Bottom board with waffle plate removed.

The Waffle Plate™

internal schematic of waffle plate

Top Layer of Top (Control) Board

Bottom Layer of Top Board

Fuse F701 on 12V input line of the top board

Blown Snubber Capacitors (Board Version)

Blown Snubbers (Blue M&Ms Version)

Beautiful Snubber Repair Job by Simon

Correct Polarity to check operation of the AC Input Relay in the Bottom Board DogHouse

Blown AC Input capacitor

Ceramic Resistors

MCU 20A Fuse under Access Cover on MCU

****An excellent collection of pictures of a disassembly and repair by Easky15 ... iLObPikOqa
[Top Level Wiring Diagrams]

Pack Quick Disconnect Locations

Here are some wiring diagrams just to get started, will post a charrger schematic after it gets traced and drawn up.




Workshop Manual High Voltage 20 Amp MCU (aka Inverter) fuse links:

There are some really good drawings to show the location of connectors and polarity of the Main HV lines into the MCU here: OBC Code 02 troubleshooting

How to access and replace the MCU fuse

see next post for troubleshooting notes
Last edited by kiev on Sat Jul 09, 2022 1:24 pm, edited 118 times in total.
kiev = kenny's innovative electric vehicle
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Troubleshooting Steps and Index

Here are some links for easy things to check:
1. 12V Aux Battery Test
2. Check or Replace OBC and EV-ECU relays in the fuse box
3. Check OBC power supply

Connectors make for quick and easy installation, but they are the most likely candidate for intermittent issues. The sliding contacts are prone to oxidation and dirt. Sometimes just disconnecting and cleaning the contacts with spray can of cleaner compound will provide a fix. With key OFF, just pull all the connectors on the EV-ECU and the BMU and clean all of them.

Troubleshooting Links:

Step 1: Diagnostic Trouble Codes from EV-ECU concerning OBC DTC for OBC

Step 2: DTC for the DC/DC Converter DTC for DC/DC

Step 3: Internal Trouble Code List for OBC OBC trouble codes

Step 4: At this point the dealer has no real repair options but to sell you a new box, or you can find a used one and replace it--it will work without any VIN re-coding needed according to jray3, who did this himself, or you can open the box and inspect for missing/burnt parts and we can try to fix it here. or maybe you could send it to an expert in Australia (coulomb or skylogger), or in USA (piev or kiev). It's heavy, ~27 lbs.

Another option may be to altogether replace the OEM charrger and converter with an aftermarket solution, such as was done here by charliejuliet.

The final option is to post your codes here and we will try to help you troubleshoot and repair your OBC.


1. Thermal imaging during charging FLIR images

2. What's touching the heatsink? Bottom Board

3. What's inside it? Waffle Plate™

4. DC Buss Capacitors Swollen Caps and Precharge Simulation

Schematics and stuff:

1. AC Input Filter and Relay

2. Output Filter

3. Solder Pads to Waffle Plate
a better version is here: ... OVV85/view

3.1 Diode drops in waffle plate

4. Low Voltage Supplies and Relay Drive description

5. Control (Top) Board Voltage Supplies discussion/measurements on page 9

6. Bottom Board AC detection circuit sketch

7. Output HV and Current sensing circuit sketches (related to skylogger's twisted sister resistor finding)

8. OBC connections and E-03 connector wiring

9. ph

Notes of parts links:

Pictures and specs for blown snubber caps, Optional caps

for TAM ceramic resistors datasheet link,

PEC 20A 450VDC MCU fuse: Available from dealer parts dept; See also the Fuse Investigation thread for the OEM datasheet (post 3) and an equivalent Littelfuse 0HEV020.ZXISO available from Mouser, viewtopic.php?f=22&t=4310&hilit=MCU+fus ... =10#p39900

and Fujitsu AC relay datasheet

12V Aux Battery Notes and Links

Simon's excellent observations and testing:

FSM testing: ... 701ENG.HTM

Charging: ... 101ENG.HTM

Removal and Installation (precautions for disconnecting negative terminal and extended d/c): ... 500ENG.HTM

DTCs related to aux battery:

Low supply voltage (C2005,2006 DTC for EV-ECU): ... 700ENG.HTM

High supply voltage EV-ECU, DTC C2007: ... 100ENG.HTM

EMCU low supply voltage, DTC P0562: ... 101ENG.HTM

OBC low supply voltage, OBC code 04: ... 600ENG.HTM

Other aux battery related codes:
DCDC Converter, DTC P0A09: ... 300ENG.HTM

ASC Traction controller, abnormal voltage readings (DTC): ... 101ENG.HTM

Last edited by kiev on Sat Sep 26, 2020 7:49 pm, edited 48 times in total.
kiev = kenny's innovative electric vehicle
Posts: 1898
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Schematics Collection Post

Schematics Collection:

Here is the pinout for the 2012 (Gen 1 USA) OBC E-03 connector, the low voltage and control for OBC and DCDC

And for the 2010 version, courtesy of 318iev

Sketch of AC input section in the fenced-in potted section of the bottom power board, note that there is a diode D301 between the relay 5V and return not shown here as it is located just outside the fence

HV Sense circuits sketches [todo kicad version]

Driver circuit sketch from page 14 [todo kicad]

Waffle Plate and Faston wiring

Output Filter Section
Last edited by kiev on Sun Nov 27, 2022 6:34 am, edited 11 times in total.
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

Thx Kenny, I’ll add to #8 that both my DCDC and charger failed at the same time, fixed by replacing with a collision salvage unit.

Simply opening and reconnecting a wiring connector will renew the contact surface and break up corrosion, but a cleaning spray like DeOx-it could only help.

It appears that the 20 amp 400 VDC fuse I blew is both the charging output and the DCDC input, would you agree? That makes me suspect only one of those two actually failed.
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

the list has nearly doubled in the last week! High temperatures to blame?
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

Not to derail the thread, but if we're contemplating replacing the charger, it would be... interesting... if we could upgrade it, to a faster rate, at the same time. Conceivable? Impractical?
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

I bought my 2012 used with 50,000 km (30,000 miles) on it so I don't know its history.

For the past 2 years I have been charging it only on 120 V L1 (8 amperes?).

I was curious what rate the cars with charger failures have primarily been charged with.
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

A few of them are from Australia where it is winter so probably not high temperature. Mine went in May, which was unusually warm this year (30 C) but still not summer temps.
Australian ones charge at 240v so more than the US L1.
DC fast chrging doesn:'t use the onboard charger so should not be a factor.
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Re: Troubleshooting and repair for On-board Charger, DC-DC Converter

RobertC wrote:A week ago one of my 2012's would not charge. I connected Canion and it showed that all 88 cells were the same voltage, ruling out a bad battery pack. When I connected the EVSE the fan would start on the battery pack as usual, and the EVSE would indicate charging, but would shut off after a few seconds. I connected another EVSE and had the same results, ruling out a bad EVSE. I suspected a bad On Board Charger. The local Mitsubishi dealer (Sport Mitsubishi in Orlando - I've had several great experiences with them) agreed, and replaced the On Board Charger (over $4,000 for the part, over $5,000 with labor) under warranty and we are back in business. I dropped the car off Monday afternoon, and picked it up Saturday morning, and they also performed the latest recall and installed new tires. I asked Sport Mitsubishi if they offered an extended warranty and was told that they did not. Our 5 year 60,000 mile power train warranty expires in May of this year for those of us who bought the i-MiEV when it was rolled out nationally in May of 2012. I repair electronics for a living now, so if the On Board Charger fails after the warranty expires I'll have a go at repairing it myself or I'll try to buy a used one because I'm not paying over $4,000 for a new one.
My On Board Charger failed on my lower mileage (30,000 miles) i-MiEV “Purple” April 2017 and was replaced under warranty. I posted my concerns at the time but did not receive any feedback on this forum. I recently sold my other 56,000 mile i-MiEV “Silver” and was glad the On Board Charger had not failed yet since it was out of warranty. I also estimate the i-MiEV that I sold had between 60-70% of its original battery capacity.
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Step 3: Internal Diagnostic Codes for OBC

After reading the EV-ECU DTCs, the dealer should use the MUT3 to read down into the Data List from the OBC to get the Internal Diagnostic Code from the OBC / DC Converter box. This gives specific circuit malfunction information that can help give us some idea of which circuits to investigate.

For most of these, the first time it occurs, the OBC will store the code. If it happens again at the next charging, then it throws the code up to the EV-EVU that a malfunction has occurred. This should cause the trouble light on dash to be lit. A few are so serious that a malfunction is indicated at the first instance.
  • 01Output voltage abnormal
    02 Load connection abnormal (main battery not connected)
    03 Output current abnormal
    04 Control power supply voltage abnormal
    06 AC input voltage abnormal
    11 Voltage command abnormal
    12 Current command abnormal
    13 EV-ECU lost
    15 Power factor correction (PFC) circuit temperature abnormal
    16 Temperature in increasing voltage area abnormal
    17 Inside ambient temperature abnormal (boost circuit rectifier temperature abnormal)
    26 Charging current limited (temperature increase)
    27 AC input current abnormal
    28 EEPROM abnormal
    29 Pilot signal abnormal
    30 Electric motor circuit abnormal
    31 Temperature in increasing voltage area abnormal 2
    32 Charging current limited (input voltage decrease)
    33 ROM/RAM abnormal
    35 AD conversion module abnormal
    39 Power factor correction (PFC) circuit output voltage abnormal
    41 Input current sensor 0 point abnormal
    42 Output current sensor 0 point abnormal
    43 Inverter overcurrent abnormal
    44 Rectification overvoltage abnormal
    45 Rectification overcurrent abnormal
Last edited by kiev on Sun Sep 02, 2018 8:33 am, edited 5 times in total.
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