2012 Leaf Charging Issues

[newtoda]

Hello all! I have a 2012 Leaf with a confounding charging problem. To make a long story short, my Leaf has suddenly stared to refuse to charge at any level, chademo included. When the standard charger in inserted, all seems normal. The dash lights flash, system beeps, and contactors seem to contact. Then, as what sounds like a pump ramps up, the lights turn off and no charging occurs. There are no lights on the charger. When chademo is attempted, the charger communicates, and acts like it is starting to charge, only to immediately disconnect as with the standard l1/l2 charger.

I have disassembled the OBC and found a blown cap and replaced it (the top cap near the three white resistors(?)). The behavior is the same. On testing at the pilot port, I get no voltage and no resistance in either direction. The D547 diode seems to test normally (1.125v in one direction, nothing in the other).

Other notes: I have fully charged the 12v battery AND used a known good. Behavior is the same. There are no CAN bus codes, just the seemingly normal charger(B29c1-236c) and P3173 from the EV/HEV). Anyone have any ideas? The L1/L2 issues seem like an OBC issue, but that shouldn't impact chademo charging, right? I'm at a loss.

Thanks in advance!

 

[cornbinder89]

Pump "ramping up" is un-usual I wonder if the PDM is getting an "overheat" sensor reading? PDM problem will kill Chademo also as well as L1/L2.

 

[newtoda]

Pump "ramping up" is un-usual I wonder if the PDM is getting an "overheat" sensor reading? PDM problem will kill Chademo also as well as L1/L2.

Interesting. My "pump" assessment is based on what sounds like liquid coming to a stop right after the evse kicks off.

 

[nlspace]

No PDM in a 2012.

Did you check the resistance thru those white ceramics--one of those has an internal thermal fuse. That would prevent AC charging.

But the lack of Chademo charging points to a possible issue with the contactors in the pack. Should be a DTC for those if defective.

Also the lack of a pilot signal points to a possible blown fuse for one of the 12V power feeds to the OBC control board, and that would affect AC and Chademo charging. Someone reported their lack of charging was due to a blown fuse on one of the 12V supply lines, so check all the fuse panels to rule that out.

 

[newtoda]

No PDM in a 2012.

Did you check the resistance thru those white ceramics--one of those has an internal thermal fuse. That would prevent AC charging.

But the lack of Chademo charging points to a possible issue with the contactors in the pack. Should be a DTC for those if defective.

Also the lack of a pilot signal points to a possible blown fuse for one of the 12V power feeds to the OBC control board, and that would affect AC and Chademo charging. So check all the fuses, i don't recall the number.

Thanks, nlspace. I've gone back and checked every fuse in all four boxes and all are good. For those in the front relay box that seem to be related to the charging, I inspected them very closely and saw no problems.

The full list of leafspy DTCs is attached.

How would I go about checking the resistance of the ceramics? The leads seem to be well hidden under the waffleplate.

Video added of the behavior for reference and just in case others experience similar issues in the future.

 

[ACDCPhilip]

Dala had exactly the same fault codes you have, as shown in his video here :-


His vehicle did charge ok with Chademo though.

 

[nlspace]

How would I go about checking the resistance of the ceramics? The leads seem to be well hidden under the waffleplate.

Here is picture that @coulomb posted to show where to measure this on the topside of the waffle plate solder junctions,



Here is the Laef board showing the position of a blown fused ceramic resistor; the resistance thru the 3 ceramics should be about 14 Ohms to the N junction from the light blue wire Faston connection.

The Faston tab connections have a locking feature; push the wire down toward the board, then grab the white connector and slide it up to release the lock, then pull wire and connector up to remove from the tab.


Just below the black capacitor you changed, is the black AC relay, they don't often fail but could be suspect also.

 

[coulomb]

To reduce confusion, that top photo of mine (someone else's original, my annotations) is from an iMiEV charger, which is similar but not the same. But it does show where the neutral pin is on the Waffle Plate™; the Waffle Plates™ are the same in the iMiEV and the 2012 Leafs.

 

[newtoda]

To minimise confusion, that top photo of mine (someone else's original, my annotations) is from an iMiEV charger, which is similar but not the same. But it does show where the neutral pin is on the Waffle Plate™; the Waffle Plates™ are the same in the iMiEV and the 2012 Leafs.

Probing between the second faston lug (marked NB L on my board) and the neutral solder joints for the waffleplate as shown in the photos above, I get no reading. I take it this means the fused ceramic is blown?

It sounds like this would explain the lack of AC and DC charging? If so, do you have any idea where on earth can I get a replacement for this part?

 

[nlspace]

I get no reading. I take it this means the fused ceramic is blown?

Yes it is likely blown by whatever destroyed the capacitor (lightning or mains power surge?). That would prevent AC charging for sure, no effect on DC.

"NB L" is the Neutral Faston junction "B" of the Blue (L is blue wire color) jumper wire. Confusing with all the B's and L's and N's. There are 3 Neutral Faston junctions: an "N", "NA" and "NB"

If there was a lightning surge then there are some surge suppressors on the board that may have also given their life to save the board. They are on the top right corner of the board where the Red and Black AC cord attaches. 3 black lollipop ZNR V20 471U, Panasonic varistors aka surge arrestors. Also a clear glass tube Spark Arrestor located just below those. And check the fuse located just below the SA. And the fuse in the top right corner.

With DC charging affected also, there is likely some damage on the upper control board in addition to that found on the lower power board. Really need to find all the damage before putting everything back together, i.e. test in place with cover off.

To properly replace the ceramic resistor involves de-soldering the 72 junctions to remove the waffle plate, but that is a very difficult task even with the right equipment. Easier to crack the resistor with pliers and remove the guts leaving enough stubs to solder a new resistor from the topside.

While you are there, check the diode voltage drops for the waffle plate to ensure that it is okay. Here again @coulomb has annotated a diagram to help with this measurement. It can be found, along with replacement resistor discussion, in the OBC thread linked to from here,
https://myimiev.com/threads/my-troubleshooting-repair-list.5619/

 

[newtoda]

Thanks! The crack and solder topside was the method I used on the adjacent cap. Much easier. I've checked the fuses and the spark arrestor (assuming that's the one with the beads inside) and all of those seem good. I'll check again for good measure when I look into the surge arrestors, etc. I'll report back what I find. Thanks again!

BTW, I think all this started when the car was plugged into a Clipper Creek L2 public charger at the local airport. Everything was fine before that. Got back from the trip and the car wasn't fully charged. Hasn't changed since. Who knows what happened while connected there.

 

[newtoda]

I have done the diode tests on the waffle plate and all SEEMS okay there (values are a little off, but directionality readings are good at each). The fuses are all good. The SA reads nothing, but I understand that is normal (?). It looks the same as one coulomb reported as good. Same thing with the varistors: no reading when in resistance. No idea if that's correct or not. Anything else I need to test in the lower board?

With the DC charging not working, is there anything in particular on the top board that's known to cause that? I've tested the diode many have mentioned as a problem, but it tests good. I'm puzzled by this. Thanks for all the help!

 

[nlspace]

Considering your symptoms (no AC or DC charging), and the extent of the damage found in the AC Input section (Cap and Ceramic R), my guess is that one or more of the low voltage power supplies on the upper control board are defective.

You might check all of the electrolytic capacitors on the control board to see if any are shorted or swollen. i would guess that the voltage regulator for the supply which drives the AC relay (located on the lower power board) might be damaged, and that would cause the ceramic R thermal fuse to get overloaded and blow.

If you didn't disconnect all the Faston tab connections then the diode check values might be a little flaky, but a waffle plate™ issue would get flagged with a DTC.

 

[newtoda]

Considering your symptoms (no AC or DC charging), and the extent of the damage found in the AC Input section (Cap and Ceramic R), my guess is that one or more of the low voltage power supplies on the upper control board are defective.

You might check all of the electrolytic capacitors on the control board to see if any are shorted or swollen. i would guess that the voltage regulator for the supply which drives the AC relay (located on the lower power board) might be damaged, and that would cause the ceramic R thermal fuse to get overloaded and blow.

If you didn't disconnect all the Faston tab connections then the diode check values might be a little flaky, but a waffle plate™ issue would get flagged with a DTC.

View attachment 5627

Testing the diode drops with a better meter, they all test spot on with the drops indicated on the diagram above. I have gone through the caps on the top control board and all read okay with the meter. None are shorted. I also checked diode 547 on the control board and it tests normal.

I've now extracted the blown ceramic fused resistor from the top. After removal, the fuse tests exactly on spec (4.7ohm) but, predictably, the fuse is blown.

Is there any way to inject 5V to test the relay? It doesn't seem so without removing the waffleplate.

 

[nlspace]

Is there any way to inject 5V to test the relay?

Yes there is. Be careful of the polarity as there is a freewheeling diode that can be blown.

It can be injected at the trace vias on the ends of diode D301, located in the center of the board just outside the fence near the AC relay.

Measure the resistance at those vias, should get about 62 Ohms, the R of the relay coil.

Apply +5V at the via of the diode bar | , located furthest from the relay, and -Return to the via closest to the relay. This is reverse biasing the diode such that it is not conducting and voltage goes to the relay coil.

The power for that relay comes down thru the white wires of connector CNA from the upper control board power supply. i think the relay gets switched by transistor TR301 located on the bottom layer of the control board if you wanted to trace it out.

With the relay open there would be about 14R from the Neutral solder joint to the NB L faston tab. With the relay engaged that should drop to nearly zero Ohms, as the relay by-passes the 3 pre-charge ceramic resistors.

 

[newtoda]

Yes there is. Be careful of the polarity as there is a freewheeling diode that can be blown.

It can be injected at the trace vias on the ends of diode D301, located in the center of the board just outside the fence near the AC relay.

Measure the resistance at those vias, should get about 62 Ohms, the R of the relay coil.

Apply +5V at the via of the diode bar | , located furthest from the relay, and -Return to the via closest to the relay. This is reverse biasing the diode such that it is not conducting and voltage goes to the relay coil.

The power for that relay comes down thru the white wires of connector CNA from the upper control board power supply. i think the relay gets switched by transistor TR301 located on the bottom layer of the control board if you wanted to trace it out.

With the relay open there would be about 14R from the Neutral solder joint to the NB L faston tab. With the relay engaged that should drop to nearly zero Ohms, as the relay by-passes the 3 pre-charge ceramic resistors.

Before injecting voltage at the vias, I checked diode D301 and it appears to be shorted open (?). I get voltage through regardless of lead position. That's an interesting development. When checking resistance at the vias, I get 1k ohms, the same measurement I get across the diode.

BUT, the relay clicks nicely upon injection of 5V at the identified vias, so that's good.

 

[coulomb]

I checked diode D301 and it appears to be shorted open (?). I get voltage through regardless of lead position.

That's to be expected with the conductance of the relay across it. The multimeter only injects about a milliamp on ohms range, and that would only drop around 61 mV across the relay/diode, way too small to cause it to conduct. You could desolder it, or just assume that it's fine.

Or if you have a power supply with a very fine current limit, you could set it to around 20 mA, and observe a lower voltage drop when the diode is forward biased. The 20 mA will drop some 1.2 V across the coil, enough to cause the diode to conduct one way.

 

[nlspace]

if you use the diode check function on the meter, then it will read very low voltage, e.g. 0.04V in both the reverse and forward direction due to current passing thru the coil in parallel.

you could desolder one end of the diode and lift it up in order to open the circuit and measure the diode drop and coil resistance.

But if relay is clacking strongly and the resistance thru the contacts is nil, then probably okay to use as is.

 

[newtoda]

I finally received a compatible resistor from digikey. That was it! We're charging again on AC! Thanks for all the help!

 

[moapys]

Congratulations @newtoda! Could you share the R value (and wattage)...plus where it was located? E.g. physically on the waffle-board, logically in the schematic? Thanks to all in this thread for the expertise and cautious troublshooting strategy!