# 2011 Leaf died when left the defrost on for 20 minutes



## braebyrn (Nov 16, 2017)

Last winter the original owner turned on the defrost, came back 20 minutes later to find a dead Leaf. She had the 12 volt battery charged and the car would turn on, shift to neutral, but wouldn't go into Drive or Reverse, no heater, no a/c and trouble lights showed up on the dash and no regular or quick charging. 

She had it towed to Nissan and they said they didn't know what was wrong and they could throw a lot of parts at it and it may cost more than the car was worth. So she sold the car. 

Owner number two buys the car, brings it to another Nissan who said it needs a new DC to DC junction box and inverter. He has a local ICE car mechanic do the repairs and it still didn't fix it. The parts were from a wrecking yard and unknown is they are good parts. I did pull the original DC to DC junction box apart and all 4 of the HV fuses are good. 

I buy it from him and see the following codes.

C118C 0109 ABS EV/HEV System BRC-126 
C1A6E 0109 BRAKE EV/HEV System BR-146 
C1A70 0109 BRAKE Brake Control System BR-160
The previous codes will always come up if the below faults are displayed.

P3176 00C0 EV/HEV Inverter Condenser EVC-238 
P311C EV/HEV High Voltage Sys EVC-204

Note:
(All following systems are disabled due to: P3176
FAIL-SAFE PATTERN
Pattern A: Quick charge prohibited
Pattern B: Normal charge prohibited
Pattern C: READY OFF
Pattern D: High-voltage power supply stop

If DTC P3176 is displayed with DTC ..P311C.. perform diagnosis for DTC ..P311C..)

I have a service manual and while going through the factory service manual, it says to check the high voltage connection at the compressor, ptc heater and some other steps. 

With the PTC heater I set my volt meter to 200k Ohms and get a reading of 71.8 which is greater than what the test said. The test said it should be 3 k ohms or more. 

I unplugged my 2012 Nissan Leaf and it shows 47.3. I did the test at the same time a few feet away from each other. So 71.8 is more that 3 k ohms right? 

I have 4 volt meters and they all seem to be a little different on the readings. Maybe its time for another one. If you reverse the leads, it sometimes doesn't even show a number. 

Oh and every hour the contactors and relays at the battery will clickit click click for a second and do that again every hour. I took at the traction battery disconnect plug and that stopped the contactors in the traction battery to stop, but I still hear the relay in the box on the drivers side go on and off. There is nothing plugged into the OBD port by the way. 

Thoughts?

I could pull parts off my daily driver and swap them to see if it will help clear the codes.....


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## gunnarhs (Apr 24, 2012)

braebyrn said:


> Last winter the original owner turned on the defrost, came back 20 minutes later to find a dead Leaf. She had the 12 volt battery charged and the car would turn on, shift to neutral, but wouldn't go into Drive or Reverse, no heater, no a/c and trouble lights showed up on the dash and no regular or quick charging.
> 
> She had it towed to Nissan and they said they didn't know what was wrong and they could throw a lot of parts at it and it may cost more than the car was worth. So she sold the car.
> 
> ...


Without knowing much about Nissan Leaf 2011 (I drove one for a few days with some issues back in 2013). I would first check if the main battery pack is OK, it might be broken. 



> I have 4 volt meters and they all seem to be a little different on the readings. Maybe its time for another one. If you reverse the leads, it sometimes doesn't even show a number.


Please get help from an skilled Electrician to figure this out as there is some high voltage measuring required


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## braebyrn (Nov 16, 2017)

Gunnarhs, 
I appreciate your concern on the safety and I understand that there is high voltage and do take the precautionary steps in dealing with it. Telling me to find a qualified electrician or someone knowledgeable of the workings of the Leaf is why I am here at DIYElectric Car forum looking for advice for a DIY'er. Otherwise I would have brought it back to a Nissan dealer and paid out the nose for something someone here may have experienced before. If I don't find someone here, and I find the problem, I will reply with the answer and maybe it will help another DIY'er. 

The main battery pack has a precharge resistor that is prone to fail when the PTC heater or the A/C compressor fail. The junction box is deep inside the battery and has a couple of contactors which I can hear them cycling once an hour with the car off. That is not normal behavior. I have 4 Nissan Leafs and this is the only one that does it. Granted two of them are 2013 models. 

I have tested the compressor and PTC heater across the High Voltage connections and get more than 3 k ohms. I have a few more steps before I drop the traction battery and open that up. 

My neighbor is an experienced professional auto mechanic. Even he is still learning the electric car diagnostics with years of training. He has won many awards and his dealership sends him on contests (just came back from one) around the country where he and other mechanics from different car brands compete. He gets paid the big bucks and still doesn't know how to fix my mess. He said to get on the internet and ask. He didn't bring it to his shop, but is pointing me to here to find the answer.


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## gunnarhs (Apr 24, 2012)

braebyrn said:


> Gunnarhs,
> I appreciate your concern on the safety and I understand that there is high voltage and do take the precautionary steps in dealing with it. Telling me to find a qualified electrician or someone knowledgeable of the workings of the Leaf is why I am here at DIYElectric Car forum looking for advice for a DIY'er. Otherwise I would have brought it back to a Nissan dealer and paid out the nose for something someone here may have experienced before. If I don't find someone here, and I find the problem, I will reply with the answer and maybe it will help another DIY'er.
> 
> The main battery pack has a precharge resistor that is prone to fail when the PTC heater or the A/C compressor fail. The junction box is deep inside the battery and has a couple of contactors which I can hear them cycling once an hour with the car off. That is not normal behavior. I have 4 Nissan Leafs and this is the only one that does it. Granted two of them are 2013 models.
> ...


Ok, let us get to work then... You must excuse my bad english...
My suspicion (might be wrong) is that the fault is in the main battery pack or DC-DC -converter which charges the 12V battery from the main pack. The easiest way to find out is measuring the Voltage on both sides of the DC/DC-converter BEFORE putting out the big battery pack.

1) Before start working put on thick rubber gloves like for gardening.
2) Set your Volt Meter to Highest DC Voltage measurement (600V for the normal ones)
3) Before switching the car on check on the 12V System. Measure the 12V battery before switching on, it should show at least 12.5 V. Then switch the car on and measure the Voltage at the 12V Battery again it should show at least 13V now.
4) With the switch still on measure the Voltage at the other side of the DC/DC converter.
That should be the battery main voltage at at least 300V (preferably more). 

Let us start with this and then decide based on the result of 3) and 4)


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## pm_dawn (Sep 14, 2009)

Can you get any info from leafSpy ?
it could help to know if all cells in the HV pack is OK.

Best regards
/Per Eklund


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## onegreenev (May 18, 2012)

Is the main battery pack charged?


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## braebyrn (Nov 16, 2017)

Update: 
The precharge resistor inside the battery junction box was bad. After replacing that and resetting the codes with LeafSpy pro, it has been functioning and driving normally for weeks. 

We tried duplicating all of the scenarios that caused it to fail, and it is still working fine. The Nissan service department ran a diagnostics on it and all checks out with them too.


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## Hollie Maea (Dec 9, 2009)

braebyrn said:


> Update:
> The precharge resistor inside the battery junction box was bad. After replacing that and resetting the codes with LeafSpy pro, it has been functioning and driving normally for weeks.
> 
> We tried duplicating all of the scenarios that caused it to fail, and it is still working fine. The Nissan service department ran a diagnostics on it and all checks out with them too.


Just out of curiosity, what sort of precharge resistor does it use?


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## electro wrks (Mar 5, 2012)

Do you have any photos of the resistor and the inside of the battery junction box?


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## braebyrn (Nov 16, 2017)

The precharge resistor is a ceramic 40 watt 30 ohm power resistor. 









The 2011 is mounted underneath the battery junction box. It is the black box on the left near the front of the battery case. 









The 2013 is a bit easier and is on top of the battery junction box.


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## gunnarhs (Apr 24, 2012)

braebyrn said:


> Update:
> The precharge resistor inside the battery junction box was bad. After replacing that and resetting the codes with LeafSpy pro, it has been functioning and driving normally for weeks.
> 
> We tried duplicating all of the scenarios that caused it to fail, and it is still working fine. The Nissan service department ran a diagnostics on it and all checks out with them too.


Thanks for the feedback and nice that everything works now


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## ShawnM (Dec 24, 2021)

Thank you for posting this, It saved me a lot of time trying to figure out what went wrong with my daughter's car. Same exact scenario, she ran the defrost for about 20 minutes and came back and the car would only go into neutral. We had the precharge resistor replaced and it runs fine now. Is your leaf still running? Did you ever find out why the resistor popped in the first place? Thanks again!





braebyrn said:


> Last winter the original owner turned on the defrost, came back 20 minutes later to find a dead Leaf. She had the 12 volt battery charged and the car would turn on, shift to neutral, but wouldn't go into Drive or Reverse, no heater, no a/c and trouble lights showed up on the dash and no regular or quick charging.
> 
> She had it towed to Nissan and they said they didn't know what was wrong and they could throw a lot of parts at it and it may cost more than the car was worth. So she sold the car.
> 
> ...


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## remy_martian (Feb 4, 2019)

Sounds like the precharge sense never reaches ~pack voltage because of the several kW discharge rate of the PTC resistor and that 20 minutes is long enough to burn a resistor out that should normally be on for less than a second or so.

Software bug in allowing the defrost to be on before the precharge cycle is done, in other words.


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## gunnarhs (Apr 24, 2012)

It would be interesting to compare the diagrams for the 2011 and 2013, this looks like a fault design in the 2011. Normally you have 2 different resistors one for the main contactor / inverter in the High Voltage (300 +) and another for the DC/DC converter. The heaters I know are normally on the low voltage side (24/12V) behind the DC/DC and should not affect the main precharge resistor for the inverter that much.
Edit: How wrong I was ha,ha. Nissan heaters seem to be directly connected to the high voltage system and the early heaters used were not even isolating properly the high voltage system from the body as it seems.
Found these useful links, explaining the old and new system





EV-OLUTION







ev-olution.yolasite.com






Climate Control System


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## MountainBen (10 mo ago)

Thank you for posting. I bought a non-functioning 2011 Leaf with the same symptoms as yours. The previous owner said it was working great until we got a major cold-snap (in Seattle) and one day he was starting it on a cold morning and it wouldn't go into drive or reverse. Today I dropped the battery and removed the contactor block. As expected the precharge resistor was dead (open circuit). 

I have not found a used 2011 contactor block available anywhere, but my plan is to take the precharge resistor out of a used 2013 contactor block. We'll see if the resistor wires are long enough or if I need to extend them. 

@remy_martian I think that's the best theory I've heard about why/how the precharge resistor fails. When I get this one fixed, I'll be sure to wait a few moments after starting the car before turning the heat or AC on to give time for the precharge sense system to shut off the precharge circuit.


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## potatocroustille (8 mo ago)

@MountainBen have you fixed the issue? I'm on the same boat with my 2012 Leaf with most likely a dead precharge resistor. I'm looking for a replacement part, but it's hard to find for 2011-2012 models. Looking at buying a 2013 contactor relay box to do the same swap you suggested. Just wanted to know if it worked out in the end. Thanks!


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## MountainBen (10 mo ago)

@potatocroustille Yes! I was able to get a 2011 contactor block from Anton at EV Rides in Portland, OR. I put it in and got everything back together in late March and the car started right up and all faults cleared. The car has been working great since then!

I also got a 2013 contractor block from Kevin at Desert Leaf Services in Nevada. The resistor is the same dimensions as the 2011 but the connectors and bracket are slightly different. You will probably need to take the sheet metal bracket off the bad resistor and put it on your 2013 resistor. Also you will need to chop the wire leads off the old resistor and solder or crimp them onto the new one to correctly reach the terminals.
Here are some photos of the 2011 resistor (2
wires) and the 2013 resistor (1 wire and 1 tab)


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## piotrsko (Dec 9, 2007)

If Y'all are going to be doing this wire changing, it's much cheaper and easier to just buy the resistor from someone like mouser online. I would even get a couple.


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## kennybobby (Aug 10, 2012)

What is making the resistor fail?









The precharge relay is shown in the pack where it bypasses the main (+) contactor.

There is a big capacitor in the traction motor inverter and in the OBC; i don't have one open to see the values but i would guess it is on the order of 1000uF. So the precharge time would be about 0.2 seconds to fill a cap from a 400V pack thru the 30 Ohm resistor. The resistor would see a heating value of about 5000 W although it's continuous rating is only 40 Watts.

So if the heater or AC were turned ON during the start to READY mode, or during the start of charging mode, then those loads might be pulling down the pack voltage such that the VCM extends the precharge period for a longer duration.
OR, 
the precharge relay contacts might be degraded, welded or frosted over in such a way to cause a longer precharging time that would blow the resistor. In either case the relay is suspect too.

It might be cheap insurance to replace the relay when swapping out the resistor just to eliminate the possibility.


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