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not charging my iON, cell or CMU or BMU problems

Posted: Fri Jan 05, 2018 2:58 pm
by czalbert
Hi all,

I have a Peugeot iON - 2011 (66.000 km). I bought with 40.000km and I used 26.000 km without any problems. One day I could'nt charge my car, started the charging and flashed the ! icon on the dashboard and stopped the charge. My mechanic read out the OBDII and we got an error code in the 10th block F cell has low voltage. I checked the Volts and I saw every 2-3 seconds drops to under 2.5 V and goes back to the normal level and the charging is stopped. I can't charge the car. I got a new cell and we replaced it.

But now the problem is still. I used the canION app and I saw a some intresting data. The cell what we changed after charging in 3-6 seconds drop down suddenly the Volts number from 3,7 to 3,2 or sometimes 0,7 V and suddenly up to the normal Volts and after this repeat 3 times and the system block the charging. I attached the picture about the cells Volts under charging and the other picture about the drops I can’t charge. I tried start the car and under pressure also drop down the Volts in random on the number 74 cell.

And after I checked the Volts History and I found there sometimes the Volt up to 6,400 Volts and after goes back to 340 Volts. (picture about that: And the battery icon on the right is red and sometimes under charging change to full (green) and suddenly goes back to red. (actually charging is 14%)

First I thought this cell is wrong but we replaced it and still the problem. After the cell replacing the OBD error code is P1A5B
I think that is not cell problem, do you have any ideas? What is that?

Thank you.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Fri Jan 05, 2018 10:34 pm
by kiev
It sounds like the cell that you changed was not bad. The problem is likely on the circuit board rather than the cell itself being bad. A single cell on a workbench can be tested by charging and discharging manually to determine it's capacity and whether or not it is defective. This could be done on the cell that was removed to verify that the cell is good or bad. A defective electrical component, or a bad solder joint, could cause the voltage readings to randomly and intermittently vary in the manner in which you described. A complete 8-cell module swap, or just the 2 circuit boards in an 8-cell module, might fix your problem. Or a re-flow of the solder joints using a hot-air blower on your current circuit board might fix it also.

Here is the Reference Info from the Service Manual on troubleshooting this code.

Code P1A5B = CMU10 battery cell low voltage abnormal

Trouble Diagnosis:

Check Conditions
This code appears after 3 seconds elapse after the electric motor switch is turned ON, or 3 seconds elapse after the main battery starts to be charged, AND
None of the following diagnosis codes occur at the same time.
P1AA8: Local CAN (for main battery) signal time-out
U1082: Local CAN (for main battery) bus off
[note: This just means that the CAN buss is working okay and is not the source of the issue.]

Judgement Criterion
The battery cell voltage is less than 2.3 V.

None available

The module 10 (consisting of battery cell, CMU board and battery cell voltage sensor) in the main battery is failed.

STEP 1. M.U.T.-III data list
Check the data list reference table items corresponding to the diagnosis code, i.e. check these items:
Item 102: CMU ID10 battery cell A voltage
Item 103: CMU ID10 battery cell B voltage
Item 104: CMU ID10 battery cell C voltage
Item 105: CMU ID10 battery cell D voltage
Item 106: CMU ID10 battery cell E voltage
Item 107: CMU ID10 battery cell F voltage
Item 108: CMU ID10 battery cell G voltage
Item 109: CMU ID10 battery cell H voltage

An OK data condition is a reading of 2.3 V or more.

Q. Is the check result normal?
If 2.3 V - 2.5V, then charge the main battery.
If 2.5 V or more, then it is an intermittent malfunction (Refer to GROUP 00).

Re: not charging my iON, cell or CMU or BMU problems

Posted: Sat Jan 06, 2018 6:34 am
by czalbert
Dear kiev.

Thanks your response.

Yes maybe it is a sensor problem. But I don't understand If it is a sensor why only the problem occurs when the car charging or running, when I checked the data under ignition the problem didn't occur.

Now I got a tip, have to change two blocks. For example change the 10th blocks with the 11th blocks and if the problem moved to 11th, it has the problem with the CMU board.

Thanks your advice.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Sat Jan 06, 2018 10:53 am
by kiev
Swapping two modules is a great idea, it may be a lot of work, but maybe it doesn't take too long to open the pack after you have done it a time or two...

When the key in at ON but not to START or in READY mode, then the main contactors in the pack are not energized and no pack current can flow.

During charging and running (READY mode), then the contactors are energized and pack voltage is exposed to outside the pack and current can flow either in or out of the pack.

Cell "F" is in the section of a module with the simple circuit board without many components and connects with a little jumper cable to the main cell monitoring board.

When you do open the pack, use a voltmeter to measure the individual voltages of each cell in the two modules before you swap them. Write this down and compare it to the values that Canion reports.

If you find a low cell then it can be manually charged back up to equal the other cell using a small variable power supply. Set the voltage equal to the cell voltage and then connect to the cell, then slightly raise the voltage and current will flow. continue slowly raising the voltage until it is equal to the other cells and the current has diminished.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Thu Jan 11, 2018 7:21 am
by czalbert
Dear kiev.

We swapped the 2 blocks and the problem still on the original (#74 cell) so it's not sensor board problem. Do you have idea what is that? It's very intresting the Volt dropping and the error code still on the #74 cell and the 10th block after we changed the 10th block to 11th block.

Thank you.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Thu Jan 11, 2018 11:32 pm
by kiev
Howdy albert,

Sorry I didn't think thru this module swapping clearly-- the cell numbers are determined by the BMU and then programmed and stored on the CMU (cell monitoring) boards located on each module. The BMU doesn't care where in the pack the module is physically located, and the CMU will still respond over the CAN buss using the module 10 CAN ID. That's why swapping the modules had no effect.

i reverse engineer, troubleshoot and repair lots of circuit boards. To me this looks like a bad solder joint or defective component (chip capacitor) in the cell F circuitry on the board.

If you are sure that the replacement cell is a good cell, then it is pointing a finger at the CMU board.
You will need to either repair the board, or replace it, or replace the entire module to solve this issue. Replacing will require a visit to the dealer to re-program the cell numbers and the VIN into the pack.

good luck, keep us posted with your progress,

ps did you measure the cell voltages with a meter while it was open? how did they compare?

Re: not charging my iON, cell or CMU or BMU problems

Posted: Sat Jan 13, 2018 8:02 am
by priusfan
The cell used by Albert for replacement was a good one. I sent it to him and I checked before...
I fully agree with kiev's comments.
I think also the trouble is in the CMU (BMS part is deficient for one cell).

Re: not charging my iON, cell or CMU or BMU problems

Posted: Wed Jan 17, 2018 1:22 pm
by czalbert
Bonjour Xavier.

Yes your cell was great and I was very sad because we replaced the cell and the problem was still. I hoped that is a cell problem, the electronic problem is harder.

Tomorrow we will check the board and thanks for the comment for kiev.

I don't know what can I do if we won't able to fix the board. I think impossible found CMU board. I will contact with the Peugeot, because now the official answer, have to change the whole main battery, but why? For the cheap Volt sensor?

So now I have to find solution.

Thanks your helping.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Wed Jan 17, 2018 2:39 pm
by kiev
i can troubleshoot and repair the board if you can't find someone nearby to do it.

Re: not charging my iON, cell or CMU or BMU problems

Posted: Fri Jan 19, 2018 1:44 am
by czalbert
Dear kiev.

We checked the board yesterday and there is no problem in the analogue section. The signal is OK to the digital component. Can the digital part also be improved?