No Heat JDM 2010 Leaf troubleshooting [SOLVED]

So I've got a 2010 JDM Leaf that I'm starting on now to get the heat going on.

On the info display no power goes to heating


It throws 4x fault codes


I'm planning to check the fuse first, and I've got a replacement PTC coming in the mail. Maybe this has been overly documented already, I found a really good youtube video on both PTC and the fuse replacement procedure. But I still like to share my progress, always good to get advice/support on this forum

Check the 12 volt battery first. I'm sure it also has a blown fuse or PTC, but it looks like it needs an accessory battery too, and that will throw extra, confusing codes until fixed..

@Dala, was the car in READY mode, there is no traction power being shown on the energy screen?

@Leftie, can you read Japanese--was there something on the energy screen or what tipped you off that the 12V was bad?

Wow that is a complicated task to get to the fuse, is there a way to test for fuse continuity without dismantling so much of the car?


https://youtu.be/u19YogcC2H8

I can't read Japanese, but several of the error codes are commonly seen with low accessory system voltage. That's assuming that "Ok NONE" followed by a code means that the code was triggered but then cleared...?

Thanks for the tips guys, the first thing I did was verify it with a good 12V battery The car originally had 15 trouble codes, all random. But after clearing everything, those 4 codes were persistent.

I started dismantling it, and wow this is surely a legendary difficulty level. After 6h I got this far, ready to lift out the PDM, but it keeps snagging in everything!



Maybe this is harder since the steering wheel is on the wrong side? Hmm...

i think you could measure continuity between the PTC pin and the Pack DC pin on the DCDC unit to determine if the fuse is blown. pin 24 to 30 on DCDC wiring diagram.

You are correct, too bad it requires a hefty amount of dis-assembly to even measure those pins!

The fuse inside was blown!


One part of the puzzle solved, but what else might have gone wrong? Is it possible to measure the PTC resistance too? It would suck to put everything back together to just have it blow straight away once the car is started if there is some other issue. I have the PTC unit backordered, but it will take some time until it arrives...

The FSM has a check for short on PTC and indicates you should measure 3 kR or more, between terminals 7 and 8 of the PTC, or between 30 and 31 of the harness connector at the DCDC JB. One test is at the PTC, the other thru the harness and PTC. Maybe it fails short and that blows the fuse.

The fuse looks similar to the Littlefuse 0HEV030.ZXISO style used for the OBC. PEC (EVFG72, pn 2737) is likely OEM in Japan, but i could not source any from PEC.

Dala said:

You are correct, too bad it requires a hefty amount of dis-assembly to even measure those pins!

The fuse inside was blown!

One part of the puzzle solved, but what else might have gone wrong? Is it possible to measure the PTC resistance too? It would suck to put everything back together to just have it blow straight away once the car is started if there is some other issue. I have the PTC unit backordered, but it will take some time until it arrives...

Click to expand...

Dala, the 2011/2012 were fairly well known for blowing that inaccessible fuse. Why in the world anyone would put a fuse in such a crazy location...

The PTC heater can go bad, blowing that fuse. When it does, it's not good because it takes HOURS to replace the fuse after you replace the PTC. This post has more information about why they go bad:
https://mynissanleaf.com/viewtopic.php?f=30&t=28105&start=20#p570600

The PTC (and fusebox) were redesigned in 2013+ so it's a different issue. It appears the 2013+ are even more likely to fail (but easier to fix when they do). However, Deklein had a bad PTC unit blow his *precharge resistor* in the battery pack on a 2013+... which required disassembly of the pack to repair.

Would it be possible for you to relocate the fuse on that car? It'd make future repairs easier.

There have been 5 separate PTC heaters for 2011/2012. The latest part is B7143-00Q0K:
https://www.courtesyparts.com/oem-parts/nissan-ptc-heater-b714300q0k/?c=Zz1odmFjJnM9aGVhdGVyJmk9MzcyMjA4NTUmcj0xJmE9bmlzc2FuJm89bGVhZiZ5PTIwMTEmdD1zbCZlPWVsZWN0cmlj

I don't know if this part resolves the problems with the earlier ones, but hopefully it does...

Update, all parts have arrived, so I continued with this.

I replaced the fuse in the PDM and glued it shut.

I then installed the new to this car PTC heater, here you can see the differences. Looks like they switched from safety nuts to normal nuts, and the software version is newer on this one. Also the output is raised from 4kW to 5kW


But after getting a new fuse and PTC heater installed, the car wont start. Looks like I have some troubleshooting to do.

I got it working! The P31E0 turned out to be a loose connection to one of the HV cables. The style which has the black plastic around it has a design fault, it's really easy to get the teeth to mis-align, which causes the cable to not seat properly. This type of cable is used between the Battery->PDM, PDM->Chademo and PDM->Inverter. It was the Chademo cable that was misaligned.

Heat on and all is solved! Thanks for looking at this thread!

Congratulations and thanks for the detailed posts. Your car must be really early production to have the 4 kW heater as original. My 2011 was fairly low serial number and it had 5 kW heater which would draw about the same power as your last photo shows.

Howdy all,

Just wondering if anyone can confirm the terminal 24-30 PTC fuse test approach for me.

My heater stopped working (10 years good service) so I've pulled it to see about repair.
Internally it looks perfect - the usual solder joints all need refreshing so I'm going through them presently, but the remaining question now relates to the PTC fuse in the Junction box. Examination of the PTC does not lead me to believe there has been any significant enough current event within the heater to cause it to blow, so I've not pulled the junction box to check it yet.

Instead, what I've done is metered for continuity from the HV-in port of the Junction box (Terminals 24 & 25) to the PTC end of the PTC heater cable (which connects to 30 & 31 on the JB).

Schematic indicates that 24 should meter to 30; and 25 to 31.

Both test OK for continuity which seems to suggest that the fuse intact as I wouldn't expect the 24-30 path to meter under any circumstance if the fuse were blown.

However - if I switch from metering one pair, to metering across the junction (so 24-31 or 25-30) I will get a continuity tone for about 20 seconds before it goes open. This is most likely just down to some filtering which is in place across the main rails somewhere in the JB (most likely in the DC-DC converter) but I just figured I raise the point on the off chance that anyone has found that you can get a good meter read across the blown fuse from the exterior pins?

In the absence of such an answer all signs are pointing towards my temperature sensor at this stage so that will be my next test.