The Troubleshooting and Repair for On-board Charger (OBC) Thread

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Staff member
May 3, 2015
The Heart o' Dixie
[Edit Feb 2024 With coulomb's help we are setting up an INDEX of this thread, hopefully this will assist folks to find frequently needed repair info,
The INDEX Link

[Edit Jan 2024 The forum software was updated and the page numbering is now different, links may not be anchored correctly (tbd)

Also there is now a 10,000 character limit, so this post had to be broken into parts.
part 2 here: #1,264
part 3 here: #1,263

This thread will be used to document the technical information and any schematics or firmware available to help troubleshoot and repair the OBC/DCDC Converter

Post #2 has troubleshooting steps and an index of this thread

Post #3 will hold a collection of circuit schematics

[edit Sydney EV video link showing a snubber capacitor repair with OBC removal]
Sydney EV video of iMiev charger repair

[Original post June 2018] There seems to be many failures reported lately (last 6 months or so)

Links to user's failures [and successful REPAIRS] in reverse order, latest at top:
[2023 edit]
##. Coulomb (July 2023). 2010 earlier version OBC in Australia. Failed isolation amplifier board in the Output Sense and Filter section beginning on page 110. Successful Repair by Coulomb

##. Philsuth (Aug 2021 }. Investigation of a 2010 earlier version OBC in Australia. Complete disassembly with some great details and pictures beginning on page 76. PhilSuth

[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.
[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 upper control board removed showing the power board and flat ribbon cable, 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,
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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.

HOW-TO Section
1. Coulomb instructs on how to release the flat ribbon cable connectors without damage,


1. Thermal FLIR imaging during charging from the Supplemental cooling thread post 43


2. What's touching the heatsink? Bottom Board

3. What's inside it? Waffle Plate™
Another view from IFAM recently posted here [img=[MEDIA=imgur]TnLK2cM[/MEDIA]]

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:

3.1 Diode drops in waffle plate
Coulomb's recent version is posted here:

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,

and Fujitsu AC relay datasheet

12V Aux Battery Notes and Links

Simon's excellent observations and testing:

FSM testing:


Removal and Installation (precautions for disconnecting negative terminal and extended d/c):

DTCs related to aux battery:

Low supply voltage (C2005,2006 DTC for EV-ECU):

High supply voltage EV-ECU, DTC C2007:

EMCU low supply voltage, DTC P0562:

OBC low supply voltage, OBC code 04:

Other aux battery related codes:
DCDC Converter, DTC P0A09:

ASC Traction controller, abnormal voltage readings (DTC):

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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
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.
the list has nearly doubled in the last week! High temperatures to blame?

[Edit August 2023 some additional links to unusual failures

Search for reports of charging starts but then stops after a few seconds,

Splatter damage to the control board from snubber hot metal, on iOnico's board,
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?
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.
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.
RobertC said:
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.
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 On-Board Charging 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
[Edit: Made correction to code 30 wording, original in red]
Probably the first thing after a failure is to get a readout of the Diagnostic Trouble Codes stored in the EV-ECU, either at a dealer using the MUT3 or using a clone device such as the i909 from iCarSoft. If you can get those codes then we can help to give some idea of which circuits to look at in the box.

The EV-ECU stores the DTCs that can be read over the CAN buss thru the OBDII port by the MUT3 or a clone.

P1A10 On board charger power supply relay circuit, low input
P1A11 On board charger power supply relay circuit, high input
P1A12 On board charger abnormal stop
P1AF6 On board charging time time-out
P1AF7 On board charger READY time-out
P1AF8 On board charging stop processing time-out
P1B0C On board charging current error (overcurrent)
P1B21 On board charger output current error

U111D On board charger CAN time-out
Diagnostic Trouble Codes for the DCDC Converter:

P0A09 DCDC converter turns off for 4 seconds or more when commanded on
P0A10 DCDC converter stays on for 2 seconds or more when commanded off
While packing my failed charger for shipping to Kiev, I took a look under the top circuit board and found the culprit, or at least one of them.
One of the two blue disc capacitors on the lower board, with about half of the disc sticking up out of the black potting compound is completely popped apart. The two big white resistors still appear fine, bright white without cracking or browning.
I'm adding a discussion that was on a PM to this thread, as it might be helpfull to others:
It sounds like you have done quite a bit of research to getting this fixed.

The CAN buss probably controls the functioning of the box so that may hinder testing, but the spare pack and 12V is a good idea.

There is also the 1 khz pwm handshake signal thru the level 1 charge port to consider.

Supposedly the charger box is not VIN coded, so maybe it could be piggy-back connected to your car's CAN and come on, but the system is probably too integrated for that to work. Something has to trigger the AC input relay and then it would need PFC voltage and current control, as well as charger output voltage and current control.

i think it would be a good idea for you to post up about this PM, your charger issue, testing, repairs, status, etc. You could either start a new one dedicated to your situation or put it in the charger troubleshooting thread.

take care,

Hi Kiev:

Before taking the charger out of the car, I took the lid off, and "hindged the top PCB over so I could look at the parts in the doghouse. I see there must be two versions, as I have seen one version with two blue thru hole caps, and another version with a vertical small pcb with SMD Caps on it. The version we have has the SMD CAPs on it. I saw on the previous thread that someone found the part markings for the caps, and came up with murata part numbers. The charger just got removed from the car, and I will be picking it up tomorrow so I can continue working on it. I can use the chopstick method of removing the potting so I can see if resistors are also blown.
The 20amp fuse in the Inverter is also blown, so that is why both the AC charger and the DC-DC Functions are both not working. Since the caps were blown away, at this stage I do not know if anything else is shorted to cause the 20 amp fuse to blow. After I fix all the problems with the components in the doghouse, I probably will need to remove the board it is attached to so I can get down to the heatsink and see if any of the MOSFETs are shorted. I saw someone say that all of the solder connections along the two white strips need to be desoldered before the PCB Can be removed from the box. I think all of the solder points along the white strips are actually the leads from the MOSFETS. So it might be able to check the MOSFETS without completely removing the PCB. Another thought I had, was that the reason it was thought that all the solder connections had to be desoldered to remove the PCB, was because the MOSFETs are fixed to the Heatsink, but the Heatsink is probably just fitted to the cooling tank with heatsink compound, causing a seal that is hard to break. This is pressured down with the PCB is pulled down when the screws in the standoffs are tightened down.

Yes I am familair with the hack to apply 12v to the pin on the QC Relay to fource the contacts to close and allow use of the Chademo port. I've built two "Electric Jerry cans" that I put inside the cargo area, and use a TDK 48V to 360v DC-DC Converter fed through the Chademo port to charge the traction battery. This allows charging from the Jerry cans, even while driving. It should be noted that this method can only be used when the car is in the "READY" state, so the car thinks the charging current comming in is the same as regenerative braking and the BMU Calculates the charge as such.

I wonder if the 20amp fuse blew just because a power surge happened, or if there is actual MOSFET Damage causing a short that blew the fuse. I have a spare battery pack that was removed from another car, that I can use as a load. I don't know if the charger will function in a dumb mode if only 240VAC is applied to the ac input, HV output is connected to my test battery, and a 12v battery is connected to the DC-DC Output. I don't know if it will work with the CANBUS Connector not connected to anything, so would it power up and just power down because of no canbus communications? This would be a great way to test everything before trying to put it back in the car.

I'll let you know what I find out when I get the unit on the bench. Look forward to more info from you, and I might cut and paste this PM Back to the thread if ok?



by kiev

Howdy sky,

Sorry to hear about the failed chargers over there in WA, but hopefully we can find a solution, especially since coulomb (Mike) in Sydney is alert to the problem. He and i have worked over several years on troubleshooting and repair of diy EV chargers.

One of the forum members has sent me his broken charger and it will be here next week. i should be able to give you an answer about repairs after i get it and clean out the doghouse.

As far as options, i think there may be two using an aftermarket charger such as from TCCH or Lear, depending upon whether or not the car has a Chademo port for Level 3 charging.

With chademo, the charger output could be connected thru the port sockets to the pack by switching on the main contactors using the dcqc relay which is located under the rear seat.

Without chademo, the charger output could be routed to the pack at the terminals located within the motor control unit and switching on the main contactors using the key switch to READY.

What is your level of comfort with handling electrical stuff? Have you pulled the charger cover to inspect for scorching or burned components?

take care,

by skylogger

Hi Kiev: I saw a discussion you had with Electronpusher in regards to repairing the charger/DC-DC Converter. Seems there are quite a few of these with the resistor and caps blown up in the "doghouse" potted section on the charger. Do you know if anyone has been able to replace these components and get a unit back up and running? Do you know if in addition to these parts, was anything else found faulty? There are two people here in Perth area with blown chargers so we are looking at what options and any updates on what can be done.

Thanks for your help,

I've been able to remove the main AC Charger board out of the box. One earlier comment in this thread from another person stated that all of the solder joints along the two white strips had to be desoldered to get the PCB out of the box. This is not correct. I fist labeled and unplugged all the wires.quick disconnect connectors. I removed the big central screw and bushing. I tried slightly prying on several edges of the board thinking it had to break the seal of the heatsink compount between the heatsink and the box. It did not look like the four standoffs had to be removed, as the holes in the PCB are larger than the standoffs and it looks like the standoffs go through the PCB without making contact.
Just by luck, I went ahead and removed the four standoffs, and tried slight prying agan, and the pcb came free. It turns out that the PCB has all the pins of the power devices soldered to in along the white strips, which fixes the PCB to the power devices and heatsink, but it is the four
corner standoffs and the central screw and bushing that mount the whole assembly to the box.

I have scraped away the rubber potting inside the doghouse, and I found in my version, there is a small vertical PCB that emulates what was two thru hole caps C121 and C122 on the previous version. Some of these SMD Caps are blown away and there is a little track damage on the small vertical daughter pcb, So I plan to unsolder the PCB and replace it with the same two Thru hole caps that were in the original version. These are 2kv voltage rated caps and the value was noted earlier in this thread with someone decoding the murata part number found on one of the caps.

If you look along the edge of the PCB between the PCB and the heatsink, you can see that all of the pins from the Power devices have been bent in a dog leg so they come out from the device as 0.2" and mount to the PCB holes as 0.1" between pins. I've used an ohm meter to check across several pairs of these PCB pads, and found quite a few measure 0R and some others measure around 200R. Unless there are several different types of devices, this looks like maybe some of these devices have gone shorted.

So at this stage, it looks like I will need to desolder all the pads along the two white strips anyway, so I can remove the heatsink and power devices from the PCB. Up inside the heatsink toward the PCB side, it looks like the power devices have been potted with the same rubber potting material that the doghouse used, so it will probably take me quite a few hours to do all the desoldering, and potting removal to get down to the power devices.

I had a quick go at attaching a photo but it did not work. I'll have to get someone to tell me how to upload images direct, or find a share site that images can be uploaded to and URL Linked to.
thanks skylogger for the information about removing the bottom board.

i've updated the first post to add links to charger issues.
and edited my posts to remove mention of desoldering for board removal.

i use a free hosting site,, for my pictures. They provide "get share links" for posting to forums which resize the photos to fit the page width. Just copy and paste the BBCode forum link from imgur into your message.
Hi Kiev: Thanks for your help with posting images, I'm still missing something, as when I cut and past it just puts the litteral text of the link, the picture does not appear on the page. Below is link to a picture of the doghose that I've removed the black potting so the PCB is exposed. In this version, you can see the reference designators of C121 and C122 In front of the vertical daughter board. You can see the vaporized
SMD caps on the daughter board and the damaged tracks. The daughter board is fitted with four pins that go to the orignal C121 and C122 Thru hole cap locations. I plan to desolder the daughter board from the pins, and then use the older style thru hole caps and solder to their original positions.
Okay i can click and see the picture.

But to make it show on the forum, you need to use the "Share Links". In the upper right hand corner of the picture while you are on imgur, there will be a pull-down menu, or it may show up to the right hand side of the picture if you click on the thumbnail of it while in your account.

Here's what i see when i click on the thumbnail and it enlarges to show the share links on the rh side.


And here is the other method using the pulldown arrow. When you click on 'get share links' a popup box will appear in the middle of the screen with the various types. Click on the Copy button for the BBC forums, then paste it where you want it to appear in your message.

p.s. Good job on getting the board out and scrapping off the coating.

p.p.s. Current Sense Resistor R232, 8L00 = 8.00 mOhm 1%, is showing a bit of thermal scorching.