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P1A15 fault on a Peugeot Ion

Posted: Fri Oct 25, 2019 11:29 am
by DKPeugeotION
I’ve just bought a Peugeot ION, which cannot drive. The history of the car, is that the car one morning, showed the yellow Hi-voltage error, in the dash-board, after a ac-charge, and since that would’t drive. The former owner has sent it to dealers and specialists, and after year given up on the car. So then I got it cheap (I guess :)). I have seen the threads about the blow capacitors in the DC-DC converter, and the fine video of repair at youtube by SydEV. I’m an software engineer (and also studied also some electronics), and it was quite manageable task, to find the two cracked ceramic capacitors, and replace them with some new ones. I also exchanged the 12v battery to a new one.
I hoped that, it had been a “turn-key-solution” afterwards, but I still have the problem with the Hi-voltage fault.

My friend has a Citroen/Peugeot OBD reader/writer, and we have cleared all the errors, but one keeps coming back: P1A15 Condenser charge timeout.
I’ve tried to measure the voltage of the main capacitor, but it does not seem to charge at all. I’ve tried to read it, though the OBD-software and with a digital volt-meter at ECU. My first thought was that a Hi-voltage device was using too much power, so the voltage never got high enough (220v?) for the computer to accept. I have tried to unplug the Hi-voltage line from the heater and the aircon-pump (which the former owner says has been giving problems, and in fact might have been changed by the dealer to repair the general problem), but I am still not able to measure any voltage over the capacitor. The main fuse in the MCU, seems to be fine, and I’m also not finding any voltage directly at the incoming orange Hi-voltage line in the MCU.
I understand that others in the forum, has had problems with the MCU measuring the voltage of the capacitor incorrectly, and my voltmeter might not able to show the short pulse (1-2 sec?) of power, but I would think that should have got some result either at the voltmeter or the OBD software.

Now I’m beginning to think that problem might not be at the MCU in the back of the car, but maybe rather somewhere near the main battery.

I’m able to read the cell’s of the battery with the OBD software, so I guess that I am able to speak to the BMU. The main battery seems to be ok.

The Car is the moment parked in a parking lot, and I have not been able to follow the Hi voltage cable under the car to the main battery, and see if anything is missing, or need a repair. But hopefully I’ll be able to that some day soon, before it gets to cold here in Northern Europe.

I havent been, on the bottom side (below the cooling plate) of either the MCU or the Charger/Dc-DC converter. Could it be a fuse (or something else) there that result in the P1A15 error code?

Any suggestions to how I should progress, and what to look for, are welcome.

Kind regards
Anders M. Hermansen,
Copenhagen Denmark.
Ps) I hope that i use the right abbreviations, and understand the processes of the car correctly, but otherwise let me know :). Thank you for a great forum.

Re: P1A15 fault on a Peugeot Ion

Posted: Fri Oct 25, 2019 1:25 pm
by kirq4e
Hi Anders,

I had the same error on my Citroen. Check my posts in this thread: viewtopic.php?f=23&t=4225&hilit=P1A15&start=10#p39124

The big capacitor is charged for a fraction of a second and cannot be easily charged because it is discharged immediately.

There are a few possibilities that can cause the error. Blown pre-charge resistor in the battery, faulty condenser or the circuit that measures the condenser voltage gives wrong data to the ECU.

When you read the error there should be a snapshot of the parameters when it occurred. There should be a Condenser voltage value. If it is different than zero then the problem may be in the measuring circuit.

You can try disconnect the fuse and with it the dc-dc converter, the big resistor besides the capacitor and two cables that goes to the bottom side of the MCU. They are connected with philips head screws. Check the photos from the other thread.

After you disconnect them clean the error and try to start the car. Be careful because there may be high voltage on the capacitor. If there is you can discharge it with the big resistor to the side but be very careful.

If the capacitor is charged then you can follow the thread and check the bottom of the MCU and change the components in the measuring circuit.

If there are no voltage then you should try to identify if the pre-charge resistor is not blown. I doubt that.

The problem at my side was faulty elements in the measuring circuit that didn't work properly when the temperature rises.

Check that and hope it is not the pre-charge resistor.

Good luck

Re: P1A15 fault on a Peugeot Ion

Posted: Fri Oct 25, 2019 2:22 pm
by kiev
Howdy Anders and welcome to the forum.

Do you hear any contactors clacking when you turn the key to try to start? What about when you plug in to chargge the pack--do you hear contactors, and fans and pump motors whirring?

Re: P1A15 fault on a Peugeot Ion

Posted: Sun Oct 27, 2019 9:01 am
by DKPeugeotION
Thanks for information.
I actually thought that the main fuse were “in front” of the capacitor, but when I look carefully I, see the cobber bus-bars directly to the Hi voltage.
I’ve tried to disconnect the black wires (from your blue circle on your photo) for the discharge resistor and the fuse, then tried to start the vehicle: still no voltage over the Capacitor.

The sound I hear, when I turn the key to on-position, is the cooling pump. A few relays in the front, and sometimes the brake pressure pump. I do not hear any relays, from below the car.
When I go to “crank” position, no sounds is heard, and only the yellow error warning is shown in the dashboard. Haven’t been able to try and connect the AC.

I guess next stop is to get the battery Pack out and see if I’m able to see a problem. I think I could use a car-lift nearby (1km), and gently tow the car to the location.

I’ve found this schematic of the main-battery.
If I read it right, the only problem should now be the Main Contactor (plus or minus), or maybe the High Voltage Fuse. I would suspect that I would have seen a fault somewhere in the OBD readings if the High-voltage fuse was blown. It could also be the low voltage signal to the Main Contactor, that does not reach its destination. It seems to be called when I read out the OBD information, but I should properly also dig further into that, before i eject the main battery.
Kirq4e: I not able to see the “pre-charge resistor” in the general loop for the MCU? I see a “resistor” in the diagram, but only in the loop for the Charging contactor, i assume a Contactor that is only closed when charging?

Are there any connectors on the Hi-voltage line from the traction-battery to the Capacitor? (I guess I should be able to read that from the schematics, but do not understand all of the codes yet)
It's Just due to playing around with the idea, that someone before me, have had a go at the problem finding, and chosen to disconnect Hi-voltage power a more “alternative” way, than though the Service plug.

Re: P1A15 fault on a Peugeot Ion

Posted: Sun Oct 27, 2019 11:13 am
by kiev
What they call the "Charging" contactor is doing what we call the pre-charge function--they are charging up the capacitor thru that Resistor to limit inrush current before the Main contactors get energized.

If you can lift the car enough to get under and inspect the cover plates, then you may see whether it has been tampered with. The cover plates can be removed to expose HV terminals, which would be dangerous to handle. Maybe someone removed those and left them loose due to the hazard? There are no HV connectors--the HV cables are bolted at each end.

The low voltage control signals for the Main Contactors come out of the EV-ECU and travel to the round C22 connector on the side of the pack. Maybe that was disturbed.

The OBD reading tool will give each cell voltage regardless of the output connection since the pack CAN buss is on a rectangular 10-pin connector C26 that talks to the cell modules.





Re: P1A15 fault on a Peugeot Ion

Posted: Mon Nov 04, 2019 9:07 am
by DKPeugeotION
Again thanks for all the fine information. The Charging (of the capacitor) resistor, now makes a lot more sense. :)

I have had the opportunity to sit in the car a few more times, and clear the error and start again, and i now able to confirm that i hear relays click'ing from the batterybox, when the key reaches crank position. I've check the main 280a fuse in the battery, and no problem there. i also checked the c-22 plug, and tried to measure that the ECU is trying to handle the relays. All the High-voltage wires seem to be connected properly.

I guess that the problem now points to the pre-charge resistor, or maybe the contactors them self.

I need to get the main battery out to find out why there's no power to the Capacitor, and thus the P1A15 error.
I'll try to find a indoor garage, where i able to lift the car, and where the temperature is a bit higer :)

One day i connected the 12v battery, and to my surprise a blower started in the main-battery. I guess its some kind of heating of the battery when the temperature is near freezing. :)

Re: P1A15 fault on a Peugeot Ion

Posted: Mon Nov 04, 2019 9:22 am
by Gary12345
hi there, i have seen on the forums a failure of the pre-charge resistor itself, located inside the battery pack....

found it here -

It also details the location of the charge capacitor - so for some reason the capacitor on your car does not reach a high enough level of charge within the timeframe. could you monitor capacitor voltage while you try and start?

of course it could get to near 400v so all usual sensible precautions apply...

good luck


Re: P1A15 fault on a Peugeot Ion

Posted: Thu Nov 28, 2019 5:27 pm
by DKPeugeotION
Sorry about the delay,
I have now been able to get the car indoor, and up on a lift.

I have had the traction battery down and out of the car, and open it up, and found the relays.
I measured the pre charge resistor, and its was a open loop, with no restance. So broken like you suggested!

I found a new resistor, of 22ohm and able to handle the current/power:

Got it installed, and remounted the battery, and now i see the capacitor charging to arround 300v with my voltmeter, but i stil get the P1A15 error.
I then connected the ODB2 Fault reader, cleared the error, and set to measurements, and when i next time crank, i see that the ECU is able to measure the same voltage (322v), and then discharges back to 0v.
I got a little video of this:

But still ends with a P1A15 error... :?

Any suggestions why this is, and what could be the cause?

Re: P1A15 fault on a Peugeot Ion

Posted: Sat Nov 30, 2019 10:01 am
by kiev
User Lic had this same error message and there is a thread with lots of good discussion and a few pictures, he replaced it with a used unit but had some VIN issues that may be resolved in the eeprom.

Somebody else had this code, and i think it was the measurement amplifier circuit on the board in the bottom plenum of the MCU.

There is a schematic in that thread above which shows a bleed circuit to drain the large capacitor. If something fails on that circuit it could engage the bleed and prevent charge up and throw the DTC.