Troubleshooting and repair for On-board Charger (OBC)

[kiev]

It looks like you have access to some very good diagnostic tool.

In the first image it shows faults that are likely caused by the low 12V battery. The live data shows 12.3V which is too low a reading for the 12V battery, indicating old, weak or worn out, definitely below acceptable.

Get a strong fully charged 12V before doing any diagnostics in order to clear up any issues with the low voltage power. The 5V and 3.3V supplies in the ECUs are created from the 12V, so any issue with the 12V will extend across many subsystems as shown in your image.

The pictures of your OBC don't reveal any obvious failure points such as commonly found with failures there, But your tool did not show a fault with the OBC,

The 12V is used to energize the Main contactors in the pack; so the lack of that function points to something upstream such as a fuse, relay or wiring fault (rodent damage?)

[kiev]

i think the P1A15 is because the main contactor is not closing and HV is not being sent to the MCU; the fault code is thrown if the voltage does not rise up to the required level in a few seconds.

The driver for the Main Contactor coil is from the EV-ECU located under the rear seat cushion. Check that 12V is reaching the EV-ECU (fuse, relay, wire, connector, etc.).

You will need to use the image link from imgur (.jpg file) along with the [ img ] tags to get it to show here.

[Slava]

battery voltage 355V
in the live data, the capacitor voltage rises only to 40V !!!

[kiev]

There is live data available for the Precharge and Main contactors (Relays in the Pack) that you might monitor while you try to go to READY.

So you are hearing the Main Contactors in the pack when turning the key to start? That is a good sign.

Possibly the Contactors were damaged by an accident or some other disconnect while current was flowing? Or the voltage measuring circuit in the MCU is not reading the pack voltage properly. See the P1A15 troubleshooting thread, but your issue seems different from all of those. This is not an OBC problem; with a P1A15 present the car will never go into the mode to allow charging [or READY] to occur.
https://myimiev.com/forum/viewtopic.php?t=4225

[Slava]

I checked the signal of the control unit EV-ECU to the main contactors:
in connector C-111 I checked pin 105,106,107.
105 and 106 - ok - at start, the battery voltage is applied and then decreases to 0.8 V
107 - there is no signal to the contactor + it's allways 0,8 v
any idea why the control unit is not signaling the contactor?

[kiev]

So it seems that the (-) and precharge contactor are being energized, but not the main (+),


i suspect the P1A15 code is thrown due to an issue with the MCU board, likely with the little hybrid board in the bottom plenum control board.

Someone made a cludge repair by adding a resistor to the op amp, another person by changing capacitors, two other guys replaced the board altogether with an AD204 isolation amplifier (likely the best solution), and one guy made his own version of the hybrid,

You may be able to get one of the AD204 boards from the designer; User Boo... added headers and glued it to the cover with fly leads,
https://myimiev.com/forum/viewtopic.php?p=43555#p43555

Can you tell us about the scan tool that you are using--is it an OEM version for Citroen like the MUT3, or an aftermarket device? It seems that nobody has a MUT over here so diagnostic ability is limited.

[treisutedoi302]

hello!

i have the same problem as few post ago. i have a 2011 i miev that doesn't slow charge. only chademo fast charge. i changed the 4.7 ohm 5w resistor and the problem was solved for 2 days. now, that resistor is broken again and if i change it is broken immediately. a little help, please?

Howdy and welcome t302, it sounds like your AC relay is not engaging and the resistor is being forced to carry the AC input power for too long a period (which it was never designed or intended to do).

The white ceramic resistors are pre-charge resistors to handle the initial inrush current into the large capacitors on the power board. After a brief time period the AC relay is supposed to engage and bypass the resistors and carry the bulk of the AC input to the waffle plate under the power board.

See posts on page 1 for pictures and links to other posts such as how to test the AC relay, etc. The relay may be defective or the 5V supply voltage created on the upper control board may be missing or some other fault is preventing the 5V from reaching/switching the relay coil.

One of the white ceramic resistors has an internal thermal fuse, the other one is purely a resistor, check them both, but do not energize the OBC until you have cleared the AC relay issue or the resistors will continue to fail.

thank you very much!
i solved the problem.

[treisutedoi302]

hello!

i have the same problem as few post ago. i have a 2011 i miev that doesn't slow charge. only chademo fast charge. i changed the 4.7 ohm 5w resistor and the problem was solved for 2 days. now, that resistor is broken again and if i change it is broken immediately. a little help, please?

Howdy and welcome t302, it sounds like your AC relay is not engaging and the resistor is being forced to carry the AC input power for too long a period (which it was never designed or intended to do).

The white ceramic resistors are pre-charge resistors to handle the initial inrush current into the large capacitors on the power board. After a brief time period the AC relay is supposed to engage and bypass the resistors and carry the bulk of the AC input to the waffle plate under the power board.

See posts on page 1 for pictures and links to other posts such as how to test the AC relay, etc. The relay may be defective or the 5V supply voltage created on the upper control board may be missing or some other fault is preventing the 5V from reaching/switching the relay coil.

One of the white ceramic resistors has an internal thermal fuse, the other one is purely a resistor, check them both, but do not energize the OBC until you have cleared the AC relay issue or the resistors will continue to fail.

thank you very much!
i solved the problem.

is a problem if i used a 4.7 ohm and 10w instead 5w resistor?

[coulomb]

is a problem if i used a 4.7 ohm and 10w instead 5w resistor?

No problem, as long as you get it to physically fit without shorting against nearby components.

[Slava]

So it seems that the (-) and precharge contactor are being energized, but not the main (+),


i suspect the P1A15 code is thrown due to an issue with the MCU board, likely with the little hybrid board in the bottom plenum control board.

Someone made a cludge repair by adding a resistor to the op amp, another person by changing capacitors, two other guys replaced the board altogether with an AD204 isolation amplifier (likely the best solution), and one guy made his own version of the hybrid,

You may be able to get one of the AD204 boards from the designer; User Boo... added headers and glued it to the cover with fly leads,
https://myimiev.com/forum/viewtopic.php?p=43555#p43555

Can you tell us about the scan tool that you are using--is it an OEM version for Citroen like the MUT3, or an aftermarket device? It seems that nobody has a MUT over here so diagnostic ability is limited.

thanks Kiev for the advice and help.
I mainly use Autel Ultra Lite in Power probe 4.
I have original programs for any brands, but Citroen is a rare guest, so Mut is absent.
I put the work on pause, but I will be back soon and I will definitely write what the reason is.
I also want to check hiter and air conditioning,
I disconnected the power wires from the inverter, but 12 V to + contactor still doesn’t go, it’s unlikely that a bad driver is in EV-ECU, so I’m still looking.