Resistance heater won't work at high SOC

[slmooreok]

Hello. I have a 2016 Leaf S 40 (original 30kwh battery upgraded to 40kwh under warranty last August). The car has just over 100k miles on it - I bought it used with only 2k miles on it, and it has been working well for me generally speaking.

The S model does not have the heat pump heater. The resistance heater will not work if the car is above 80% or so SoC. While in the nonworking state, LeafSpy shows a B2772-00 09 HVAC PTC Heater Voltage HAC-75. When the heater is working, no codes are shown.

I know this is an expensive repair at the dealer, but it just seems odd, how it only fails at a high SoC. I'm not sure it is worth an expensive repair bill vs just not charging the car all the way up (I don't need that much range on my daily commute).

 

[SergeantPluck]

Hello. I have a 2016 Leaf S 40 (original 30kwh battery upgraded to 40kwh under warranty last August). The car has just over 100k miles on it - I bought it used with only 2k miles on it, and it has been working well for me generally speaking.

The S model does not have the heat pump heater. The resistance heater will not work if the car is above 80% or so SoC. While in the nonworking state, LeafSpy shows a B2772-00 09 HVAC PTC Heater Voltage HAC-75. When the heater is working, no codes are shown.

I know this is an expensive repair at the dealer, but it just seems odd, how it only fails at a high SoC. I'm not sure it is worth an expensive repair bill vs just not charging the car all the way up (I don't need that much range on my daily commute).

I seem to have exactly the same problem - heater doesn't work at a high SOC and displays the same error code. When the heater does work, it works perfectly. So I can't believe there's a problem with the actual heater. Can anybody throw any light on this?

 

[cornbinder89]

I'm not finding a lot on the DTC in the 2015 service manual. It does say it is PTC voltage related it says to inspect the PTC harness if no problem found "replace the heater". I am paraphrasing a bit
Because you only see it at high SOC and works normally at lower, I would wonder about a bad (high resistance) connection the the PTC wiring. The monitor expects to see "system voltage" and is seeing slightly less. I'm just guessing here, but checking the harness connections is a lot cheaper than replacing the grid, and finding that didn't fix it.

 

[SergeantPluck]

I'm not finding a lot on the DTC in the 2015 service manual. It does say it is PTC voltage related it says to inspect the PTC harness if no problem found "replace the heater". I am paraphrasing a bit
Because you only see it at high SOC and works normally at lower, I would wonder about a bad (high resistance) connection the the PTC wiring. The monitor expects to see "system voltage" and is seeing slightly less. I'm just guessing here, but checking the harness connections is a lot cheaper than replacing the grid, and finding that didn't fix it.

Thanks for the reply. I will see if I can get it checked.

 

[BillAinCT]

The monitor expects to see "system voltage" and is seeing slightly less. I'm just guessing here, but checking the harness connections is a lot cheaper than replacing the grid, and finding that didn't fix it.

Or the actual circuit that's measuring this voltage could have drifted due to component age. Is there a schematic for this circuit? Typically a voltage divider is used to a low voltage AtoD. Dividing way down in a case like this doesn't take a lot of drift to make a big difference.