Nissan leaf wont start -

Some days ago my leaf 2011 refused to start go into drive mode. It showed both the "EV Warning Light" and the "battery warning light". I think the "EV warning light" was the first to light, and it did so during driving. afterwards it refused to start.

The local mechanic had it for a couple of days, but decided that he couldnt help me because i wasnt familiar with Nissan. And he couldnt get the car started with a jump starter although his testing said the 12v battery was ok.
At least he is honest. Problem is there is no Nissan workshops around and one has to take ferry to get to one, which is maybe not the best idea given the situation.

I did som "googling" and decided to try recharging the 12 v battery at home and bring it to the car. It worked and i was able to drive the car back to my home. I also bought a new 12v battery and charged it to rule that out. After a couple of minutes the EV warning light comes back. When leaving the 12 V battery in that car, as one normally would do, the car wont start, not even after a reset. So there must be some kind of parasitic drain in the 12 v system. The car will only start just after replacing the 12 v with a newly charged battery.

I had the mechanic have a look at the car again today and he showed me the error codes, which he said he didnt know what to do with. But he would help me out with replacing parts if I could pinpoint the problem.

The errors read by his diagnostic tool was:
B2631
C1A62
P31E7
P0AA6
Im most worried about the last one. from what I have read on these forums the price of repairing something in the HV system will most likely excede the value of the car.
Does anyone know if the P0AA6 can be caused by problems in the 12V system? I have read about testing for parasitic draw using voltage drop across fuses. My hope is that the solution is in within the 12 v system and not the HV system.
Any thoughts and comments on this would be appreciated!

You could have posted this in the original topic and the same people would have read it. I'll leave the new topic, though.

Can someone post the descriptions for those codes?

Check the voltage of the 12v before and after plugging into the car.
Confirm if there is any drain.

If there is, isolate the issue by pulling fuses and repeat

There didnt seem to be any faults on the 12 v system, although it seems to drain the 12 v battery from 12, 67 V to 12,48 v in 3 days. So maybe the HV somehow drains it. The 12 V battery is new and the behavoir is the same with old 12 v battery.

LeftieBiker said:

You could have posted this in the original topic and the same people would have read it. I'll leave the new topic, though.

Can someone post the descriptions for those codes?

Click to expand...

I searched the forums but didnt find a topic that discuss the exact same set of behaviour and fault codes. Have i overlooked something?

the description i have found are:
P0AA6 - HIGH VOLTAGE SYSTEM ISOLATION
the others are
B2631 is about sunload sensor or AC: https://www.autocodes.com/b2631_nissan.html
P31E7 is start inhibition (because of P0AA6 i guess)
C1A62 - BRAKE CONTROL MODULE POWER SUPPLY

An assortment of unrelated codes is common with a weak or low 12 volt battery, although the sunload sensor (A/C related) is unusual. At this point I don't have a diagnosis for you either, I'm afraid. Even a parasitic load wouldn't prevent the car from starting with a 12 volt battery reading more than 12.1 volts. There may be both a parasitic load AND a problem with one of the switches that inhibits starting when the car isn't in Park, your foot isn't on the brake, etc. Usually there is an error message displayed on the dash for those, though.

Common things being common, my thoughts are poor terminations or insulation damage. Insulation damage is bad news, so I suggest focusing on terminations: look for rust or loose connections starting from the 12v and ending at the DC/DC converter.

Don't get electrocuted. I think the HV system has to be de-energized

As others have already posted, check/clean connections associated with the 12V system. Pay particular attention to 12V negative cable and ground connections. There is a chassis ground connection in the negative cable that looks like a cable clip to secure the cable (one bolt), but is actually a ground connection to the fender near the battery. I found that connection marginal on both 2011 and 2015 so I cleaned the clip and the area on the fender where it attaches to eliminate excessive voltage drop on each car.

It sounds like your car will go into READY mode so you can drive immediately after installing a 12V battery. It is likely that disconnecting/reconnecting (or replacing) the 12V battery clears the errors enough to allow the car to be driven. 12.48 V after the car has been parked for 3 days is probably normal and not indicative of excessive parasitic current draw from the 12V system.

I am also concerned about the HV battery isolation error. Has there been any work on the HVAC system recently? The A/C compressor is hermetically sealed and operates from the HV battery. If the wrong compressor oil or refrigerant was added to the system, it could cause leakage current to ground and cause the battery isolation error. The heater is a resistance element immersed in liquid coolant. Failure of the heater usually blows HV fuses, but it might be possible to have a very high resistance ground fault cause the HV battery isolation error.