Auxiliary battery drain when parked causing EV system Fault

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misterbishi

Member
Joined
Oct 11, 2018
Messages
19
Hi guys,

I've got a 64 plate GX4H which I've had since September 2018. It has mostly performed well apart from a phantom drive bettery drain about once a week while parked at work, resulting in the battery level indicator dropping from around 2/3 full to 1/2 full while the car left parked, with a loss of 4-5 miles in range.

However, during the last 2 weeks, this has happened every day. As this was during the recent cold spell, I just put it down to a temperature-related issue, although it was annoying.

Yesterday morning, when I went to do the preheat via the mobile app there was message saying something like it had failed to charge. On checking the car I had an EV System Fault, along with a Brake System Fault and an ASC System Fault.

I called my Mitsubishi dealer, who informed me that the auxiliary battery was probably flat so I put it on charge and went to work.

On returning in the evening the car was completely dead, so I borrowed another charger with a fast charge option and left it charging overnight. I did initially try a trickle charge, but the battery would still discharge despite the charger being connected.

This morning the car had come back to life and had even started charging the drive battery. I noticed that the battery was still not fully charged according to the charger, but the car started up ok so disconnected the battery charger and left it charging the drive batteries.

About 10 minutes later, I was curious to see if the auxiliary battery was being charged from the mains, so I went to open the bonnet only to see the red chaging light on the dashboard rapidly flickering on and off. I tried to start the car but the EV System Fault was back.

I decided I needed to try and confirn if the auxiliary battery was good or not so I disconnected it from the car and took it to be tested by a local garage who confirmed it was good, although the coltage ws a little low. I tested it myself, and found it was around 12.8V and slowly rising when not connected, but only 11.4V when connected to the car. This seemed to indicate the issue was with the car somewhere, so I got it started by connected the fast charger again and drove the 15 miles to the dealership (all on battery).

The dealer hooked it up to the diagnostic machine, but there were no faults stored, and on testing the battery it came back as good (90% capacity remaining) and the voltage was normal. He also put an ammeter in series with the battery and told me it read about 100nA when the car was switched off.

I then got him to hook it up to the charging point, at which point the charge indicator started flickering again and despite disconnecting and reconnecting the chargng cable a dozen times, the car would not charge.

The dealer decided to go and get a torch so we could inspect the pins on the charging port more closely when suddenly we heard the charging station click and it began charging. After this it started charging every time, and after disconnecting and reconnecting the chargng cable another dozen times, we gave up and decided all we could do was monitor the situation to see if the fault returned.

On arriving home, I went to plug the car in and the charging indicator started flickering again. This time it only took one reconnection to get it working though. The voltage across the aux battery seemed ok (about 13.8V I think), although it was slowly falling again, and when I checked the current draw with everthing turned off, I got a reading that fluctuated between 1A and 1.5A. I tried to pull some fuses to see if I could pinpoint what was draining the battery, but the only one that seemed to make a difference was the IOD (Ignition Off Drain?) fuse, and it was getting cold outside so I called the dealer but he was not there, and despite requesting a call back I did not manage to speak to him again.

I let it carry on charging the drive battery until switched off by the timer a 5pm, and plan to let it sit overnight to see if the aux battery is flat in the morning. Out of curiosity I measured the voltage across the aux battery while it was charging the drive battery, and it was around 14.5V so it seems that charging the drive battery also charges the aux battery.

Has anybody else had an issue like this, and if so what was the outcome? Sorry for the long(ish) first post, but I wanted to include as much detail as possible.
 
Kesto said:
Nope I had two OUTI PHEV in the last 4 hrs

Did you mean years? :)

I just checked again and car is still starting ok. Voltage is ( steady at?) 12.5V and current about 1.8A switched off and not plugged in. Plug it in and I get 14.4V and a current of 5.4A.

Let's see what it's doing in the morning.
 
Sounds like a bad connection somewhere. Start by spraying contact spray in the connector holes of the car socket (especially the low voltage "communication" socket) Tighten the 12V battery terminals.
 
I have come to the conclusion that jaapv is right and it is a bad connection in the charging port. I noticed that when I plug in the charging cable or enable/disable charging via the app (by setting a timer so that it is not charging and toggling that on/off) I can an instantaneous current drain while the charging circuit initialises the connection.If this were to happen when the charging indicator was flickering on and off I could see how the auxiliary battery could be discharged very quickly. Only issue is I haven't been able to cause the flickering to happen since yeserday afternoon, so I can't test my theory. On the other hand, this is also a good thing ;)

However, I am still getting a 1A drain on the battery when the car is parked, which seems a bit excessive and would result in my auxiliary battery being flat over the course of a weekend if not used.

I will call Mitsubishi tomorrrow and see if the constant 1A current drain is correct.
 
Any update?
I have the same issue and being fed nonsense by my Mitsubishi dealer stating the 12v battery is not designed to last more than few days unused :eek:
When I challenged this they tried to tell me that all car batteries are the same and would struggle to start a ICE if left over a week.
It's shocking that they could event make such comments. Do these people think I have never owned other vehicles before and left them parked unused for weeks when not in the country.
 
Balderdash. The 12V battery does NOT start the ICE, the generator, fed by the main battery does. Your dealer does not sound very expert. To put it mildly.
 
abbs said:
Any update?
I have the same issue and being fed nonsense by my Mitsubishi dealer stating the 12v battery is not designed to last more than few days unused :eek:
When I challenged this they tried to tell me that all car batteries are the same and would struggle to start a ICE if left over a week.
It's shocking that they could event make such comments. Do these people think I have never owned other vehicles before and left them parked unused for weeks when not in the country.

I left my previous car in a car park near Heathrow for a month while I visited family abroad and it started first time on my return.

To answer your question, I don't think the problem is resolved, as the main battery had lost a significant amount of charge while I was at work, about 15% down from when I parked. This meant I didn't make it home on battery, which I am usually able to do.

On getting home, the car was playing up a bit; the interior lights were flickering, and when I switched it back on to check if the charger was connected properly the battery warning light came on.

I just checked it now and there is noticeable difference in the brighness of the interior lights when the drive battery takes over, and the low batteru light stays on every second start. Additionally there is a strange "whining" noise for a few seconds when I either put my foot on the brake or release it. It can't be right and I'm worried about driving it now.

Gonna ring the dealer tomorrow and inisist he takes it in for a few days to diagnose what's going on. If not then I will take it to another dealer. I tried to contact Mitsubishi, but they are totally useless and tried to tell me that the charging timer bug reported in another thread was as designed and I shouldn't expect to be able to both charge and heat my car from the mains using the builtin in features.
 
abbs said:
Any update?
I have the same issue and being fed nonsense by my Mitsubishi dealer stating the 12v battery is not designed to last more than few days unused :eek:
When I challenged this they tried to tell me that all car batteries are the same and would struggle to start a ICE if left over a week.
It's shocking that they could event make such comments. Do these people think I have never owned other vehicles before and left them parked unused for weeks when not in the country.
Unbelievable. Please name and shame the dealer.
 
I still have problems, althogh today I made it to work and back on a single charge. The battery meter was the same when I left work as when I parked, but the guessometer was 3 miles lower.

However, on plugging it in at home the charge indicator on the dash started flickering and it took about 3 attempts at plugging it in to get it charging. What a palaver! I should be able to just plug it in and be confident that it will charge correctly overnight but now I have to spend several minutes messing around making sure it will charge before I can go in the house!

I did reset the wifi module last night to remove my Nexus 7 tablet that no longer boots; let's see what difference that makes. I have asked my dealer to upgrade the software to the 14 digit code version so I can use my S7 edge with it, but he seems reluctant to do anything about it.

Additionally, Mitsubishi customer support are not replying to my emails either, so that shows how much they value their customers....
 
My technique: If they don't answer the mail, pick up the phone and keep asking for their supervisor at each step up the corporate ladder. If you keep making a nuisance of yourself you will be called back in the end by somebody with half a brain.
 
I got an EV system fault error (EV Service Required or something along those lines) today after the car had been parked for a few days up north. Temperature was -10C, the drive battery was at about 80% SOC, and I had run the remote heater for a few minutes before departing. Despite the error message the car seemed to work so I headed off. After about 25km the car went into turtle mode and then shortly thereafter stopped since the drive battery was depleted. I had two kids in the car on a remote road, yikes! Luckily all that was needed was to power off the car and restart it and the ICE then started. I assume the initial part of the trip in EV-mode was enough to charge the auxiliary 12v battery and get the system back to "normal".

I find it ridiculous that the auxiliary battery isn't kept charged by the drive battery when the car is not powered on. In retrospect I did notice that the interior light was fairly dim when the opening the door, so had I been more alert I could have charged the 12v battery a bit before departing.

Does anyone have a work-around (i.e. to force the car to charge the 12v battery)? The 12v battery is over 4 years old, but I should be able to leave it a few days in cold weather without having to charge it. Seems crazy to be charging both batteries separately.
 
nils944 said:
Does anyone have a work-around (i.e. to force the car to charge the 12v battery)? The 12v battery is over 4 years old, but I should be able to leave it a few days in cold weather without having to charge it. Seems crazy to be charging both batteries separately.

From the OP -

"I let it carry on charging the drive battery until switched off by the timer a 5pm, and plan to let it sit overnight to see if the aux battery is flat in the morning. Out of curiosity I measured the voltage across the aux battery while it was charging the drive battery, and it was around 14.5V so it seems that charging the drive battery also charges the aux battery."

Is it unreasonable that a small 4 year old light duty lead acid battery might well discharge itself after several days at -10c?
 
so it seems that charging the drive battery also charges the aux battery."

That doesn't seem to be the case, at least not for my 2014 MY car. I had charged the drive battery the day before departing. Also, when I updated the navi map some weeks ago (a very long process) the 12v battery nearly died despite the car being plugged in. I had similar error messages then, but wasn't able to get the car to respond at all until I had charged the 12v battery. It may be that episode killed the aux battery - they say that batteries do not die, they are murdered :eek:
 
nils944 said:
so it seems that charging the drive battery also charges the aux battery."

That doesn't seem to be the case, at least not for my 2014 MY car. I had charged the drive battery the day before departing. Also, when I updated the navi map some weeks ago (a very long process) the 12v battery nearly died despite the car being plugged in. I had similar error messages then, but wasn't able to get the car to respond at all until I had charged the 12v battery. It may be that episode killed the aux battery - they say that batteries do not die, they are murdered :eek:

Mine is also a 2014 MY car and it definitely charges the AUX battery at the same time as charging the drive battery. It does not charge if the drive battery isn't charging though, so just leaving it plugged in won't necessarily charge the AUX battery.

From my experience, the battery can go flat in a day or so although I seem to have a large parasitic drain on mine. I charged my car every night last week yet on the Friday morning it was as dead as a dodo.
 
After some investigation, I have determined that I do not have a large parasitic drain on the AUX battery so that is a relief. I still have an issue with the drive battery losing charge while parked, which even caused me to have to use the ICE on Wednesday to get home, which I don't normally need to do.

I also managed to measure the current drain when connecting the charger, and was lucky because when I connected the charge cable the first time, the charge indicator started flickering. I could see a constant 5A drain for as long as I kept the cable connected. On disconnecting the cable it went back down to 10-20mA. On reconnecting the cable, it connected properly and I could see a 5A drain for about 30 seconds while the car initialised the connection to the EVSE, after which it droppped to 10-20mA (the car is set to wait until the morning before charging).

I now have several videos of the flickering charge indicator, which the dealer has also witnessed, so the car is booked in for them to investigate next week. I have an OBD adapter on order so I will monitor the state of the drive battery to see if I can get to the bottom of why the drive battery loses charge while parked.
 
abbs said:
Any update?
I have the same issue and being fed nonsense by my Mitsubishi dealer stating the 12v battery is not designed to last more than few days unused :eek:
When I challenged this they tried to tell me that all car batteries are the same and would struggle to start a ICE if left over a week.
It's shocking that they could event make such comments. Do these people think I have never owned other vehicles before and left them parked unused for weeks when not in the country.


What the dealer said?? He never went to vacation, I guess. Dumb dealer!
 
Picked up my car from the dealer today. Apparently the lower pin on the charging port had come loose and had been pushed in (the dealer and I noticed it was shorter than the others when trying to diagnose the fault previously, but thought it meant to be like that as a safety feature). They just needed to tiighten it up and it should be ok now.

They also updated the wifi module software, but couldn't tell me what the new password is. The old phone I was using to control the pre-heat no longer connects and shows an authentication error when I try to register it so I suppose I need to contact Mitsubishi UK in the morning.
 
misterbishi said:
However, on plugging it in at home the charge indicator on the dash started flickering and it took about 3 attempts at plugging it in to get it charging. What a palaver! I should be able to just plug it in and be confident that it will charge correctly overnight but now I have to spend several minutes messing around making sure it will charge before I can go in the house!

This is one of the faults we have on 2 of the 3 vehicles we have here. Was reported to the selling dealership at the 1st service last year, but they didn't do anything with it. Trying again with a different dealership now the second services are booked, but they are trying to pass the buck. Exactly the same issue, takes about 3 goes at plugging and, unplugging, plugging in again, before finally the charging starts. It is indeed a palaver, as if you just plug in and walk away, there's a good chance that you come out a long time later and still have an empty main battery. :(

misterbishi said:
Picked up my car from the dealer today. Apparently the lower pin on the charging port had come loose and had been pushed in (the dealer and I noticed it was shorter than the others when trying to diagnose the fault previously, but thought it meant to be like that as a safety feature). They just needed to tiighten it up and it should be ok now.

Now, why could dealer no 1 here not have done that last year, and why is dealer no 2 here so reluctant to do it this year?
 
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