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Leaf - Gen 2 PDM/OBC/charger no output power - L1/L2 charging

7132 Views 119 Replies 4 Participants Last post by  evVanagon
I'm having a problem with L1 charging all of a sudden. This vaguely coincides with the time I put dielectric grease in the J1772 port for the winter and when the temperatures started to drop.

  • 2015 nissan leaf OBC
  • 2013 24kWh battery
  • 0 to -14C temperature outside. Battery temp is always above zero (i have the battery externally heat traced).
  • Resolve EV VCU

- When this first problem started in the fall with temperatures dropping, but with the battery well above zero, I originally plugged the EVSE in overnight and the next day it dropped 40% overnight. Indicating no charge. Then noticed with my smart outlet that there was no current draw from the vehicle. Strange. So i started investigating.

What's happening is the EVSE plugs in, I have verified the light on the EVSE says charging, I have verified the OBC is getting 100V AC inside the OBC. The OBC also registering 100V AC after the black relay before going into the underside of the OBC. So i know the OBC is getting AC voltage from the house. The EVSE does not complain with any fault lights or error messages. I have tested two different EVSEs. One stock Nissan EVSE that i've used since day 1 and my evse. Both show that they start charging but 0 Watts are being drawn from the vehicle's OBC.

  • I check LeafSpy Pro, I am seeing a 1-2A (300-600W) draw from the battery when the car wakes up by the presence of the J1772 plug being connected.
  • I have pulled apart the OBC top and bottom to check from any blown components. Nothing seems out of the ordinary.
  • The OBC is getting 100V through the EVSE properly.
  • Disconnecting the HV battery mains at the EVSE and checking the output of the OBC. I'm getting around 2-4Volts DC. This is strange.
  • I have checked the D400 (or D408?) diode and the D108 diode inside the OBC. Traced it from the control pilot circuit. They seem fine. D400 has ~11Mohms of resistance forward. And 0.542V with the multimeter's diode tester. If I jump diode D400, then the evse will stop charging and report a Diode check error. This helps me eliminate the diode as a symptom.
  • D108 also seems to be fine and reports 0.352V in the forward direction.
  • PP pin to ground is 4.74V DC
  • CP pin to ground is 11.78M Ohms forward
  • With logging EV-CAN messages. I'm seeing 0x679 register when J1772 plugged in. 0x390 - OBC_AC_status voltage is 100V, 0x390 - OBC_Charge_Power report 0kW. I'm seeing 0x390 and OBC_Charge_Status=charging or interrupted. Ox1DB seeing LB_Current with -0.5 to -1A.
  • 12V battery is charged and tested to be good.

Other things I noticed while in there:
Also, in this investigating R8000 and R80008 seem to be shorted. And with a magnifying glass I was able to see "0" printed on the top which makes me beleive these two resistors are just "jumper" resistors in the form of a SMD component.
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Is it a nissan laef OBC, or what is it?

where are you located that used 100vac for the mains?
total volts reading 511 is a problem; how can it read such a higher voltage than the pack?

182863873 - 0x1DB - Total voltage=511.5V & LB_Current=[51] [-]1.5A & LB_inter_lock=Not interlock connected & LB_MainRelayOn_flag = No-permission

What could be intemittent with the interlock? Dielectric grease get into any HV connector contacts?

Can you wire up to use 240vac (Level 2)? Maybe the 100 vac level 1 is too low for the OBC to turn On.
i think there is a thread about the details of the Gen 2 OBC.

If you are reading the 243vac at the little blue bubble above the 5VDC, then this indicates that the AC Input section is working, the fuse, EMI filter, precharge resistors and AC relay would be ok. Also the command to turn ON the relay from the control board was working, so the I/O signals thru CN100 are probably okay.

With the power OFF you would measure about 10 Ohms from the AC input Neutral over to the blue bubble, this is thru the precharge pair of ceramic resistors, one of which may have an internal fuse.

From the 243vac bubble the ac needs to get rectified thru a diode bridge, then it goes thru a switching PFC boost section to create a high voltage DC buss.

This then gets switched thru an H-bridge into a boost transformer to get even higher voltage that can be rectified and filtered in the HV Output stage, which feeds back to the pack.

Check that 30A fuse near the pack, plus check all the fuses you can see.

The OBC is smart enough to know when it has issues and stores fault codes, then send notice to the vehicle control unit that issues DTCs and warning indicator lamps.

If you could get the DTCs it would tell you exactly where the fault occurs.
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The 2 tall ceramic tombstone resistors are for the precharge circuit that bypasses the black AC relay. On previous version they were ~5 Ohms each; looks like they are a bit higher now, so the total is about 17 Ohms.

But if you were getting the 243vac over to the blue blob, then the precharge and relay were working okay. The AC input is getting turned ON.

i think the shindingen is the bridge rectifier to convert the AC input to DC,
Rectangle Font Parallel Musical instrument accessory Circuit component

You would need to use the diode check function on your meter to test a diode, see the pinout in the photo.

i can't find the thread with the PDM/OBC teardown showing the boards, but this one is good

Stand alone OBC/PDModule EV system Can 2015 - SOLVED

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0x1DB - LB_MainRelayOn_flag is always "No-permission" in my logs and in mux's it is "Main Relay On Permission". This is interesting because I can put the engine in D and get power to the wheels.
That is not good, should not be able to drive while charging.
the "main-relay" It is an odd expression. There are 2 main relays in the pack, which we normally call Main Contactors to avoid confusion with low voltage relays. i wonder if this could be the "M/C relay", the motor control relay? That would make more sense because the 2 main contactors have to be energized in order to charge the pack or drive.

This diagram is for gen1 cars, i've never been able to find one for the gen 2 with the integrated PDM.

Schematic Font Parallel Engineering Technical drawing

This might be a good time to check out the work of Dala the Great, he is the expert for leaf controls.
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Maybe it's the little white relay on the Lithium Battery Controller (LBC); x01DB is carried in the HVBAT section of the dbc, where dala's notes indicate that is the LBC. That relay is used for checking the insulation resistance.

Passive circuit component Circuit component Green Hardware programmer Electronic engineering

Can you run laefsypy to read the DTCs?

What was the story with the 511 VDC pack voltage? And now it's reading ~5V
Input 243VAC, and the OBC is outputting 5.42VDC.
The VCM or OBC checks that AC is available on the input side and measures the pack voltage on the Output side, before it will turn ON charging. It sounds like a fuse on the output side is open such that it can't read the pack, or a main contactor is open, etc. Something is not making sense to have 5.42VDC output on OBC.

Do you have another EVSE that you could try to rule out basic issues?

Sorry without a schematic i'm not much help here, i'm not set up to do anything with the CAN logs.
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Ok i see that output board on johu's video, and now i understand the 5V. But there was an error previously when the control board was reading 511V.

i've never tried running a charger unloaded but i'm sure it will set fault codes in the OBC, maybe temporary or permanent.

Has anyone else ever tried to run a charger when not connected?
Have you had any really cold weather lately? It sounds like charging could be prevented while the heater is working to raise the temperature.
Good find there on the DTC.

Many times those U1xxx codes show up when the 12V battery is weak, but maybe this time it is a real fault.
re # 4. i wonder if the OBC output filter could somehow be shorted thru the rectifier stage such that it is drawing current from the pack? just a crazy idea

i think # 3. is causing # 2.
So you have a 6.6kW charger?

If i understand the story, the charger has been working fine for several months, then it quit?

Do you know or think that the U100A only showed up after the OBC quit working?

Seems odd that a CAN buss message could be missing and it would work, then suddenly not work.

A hardware fault could cause a message issue, but which message...? And which hardware?

Since you have it open might as well check the diode drops of the HV rectifiers that feed the transformers, and the switching fets of the H-bridges, there are freewheeling diodes in the fets/igbts. Same for the fets on the PFC section, check for diode drops and look for shorts.
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For diodes and transistors, check using the diode function.

For transformers, check using resistance.

Suspicious of diode reading the same in both directions, or no reading. There may be some conformal coating on the board that would need to be cut thru in order to make connections.
Can you read the part numbers of the diodes which have strange readings, e.g. open both directions, time to look up the datasheets.
For the diodes that read the same both directions, or shorted, or open--you might be able to use your soldering iron to wick away some solder and lift one end off the board. Then recheck the diode function. If you remove one entirely from the board just be sure to mark the part and the board to get it back in the correct direction.
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i'm guessing V=power supply voltage, G=ground/return, and S=Signal;

What are the pins in your picture, where is pin 1? What is on the other side and what components are under the black coating?

You might check continuity of the hall sensor leads numbered left to right, 1 goes to Vcc supply, 2 goes to return, 3 is the Output signal that may be an input to an op amp chip.

PET1 may be a TPS79147DBVRQ1, a low drop out voltage regulator chip, 4.7V 0.1A, datasheet

Check if pin 5 of PET chip goes to pin 1 of the hall sensor.
If you can power up the little board with a power supply, then monitor the Output Signal while moving a small magnet in and out from the surface of the hall sensor you should see the voltage change. Also flip the magnet over to use the opposite polarity and repeat the test.
That's a great find there.

so your sensor reads the "zero" current correctly at 3.16

the magnet polarity (N or S pole) would make the voltage rise or fall from the zero reading.
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