High idle current drain at 12V

[r32190]

My ze0 has failed to start/shift/charge two months ago. Everything was fine before the incident, charged to 80% at night but failed next day. DTC with C1A6E-01 C1A70-01.
Tested with 13.5V charged small battery, even enhanced with Maxwell 58F supercap to provide good transient demand.
Unloaded the HV battery, confirmed with 380V output, enabled by special kit for the relays.
Checked the precharge resistor with 30 ohm, inverter input capacitance 1mF. Both are the same as normal leaf.
Running out of idea.

One indirect clue is 12V current drain during idle, which is 7.72A (with or without supercap). Never seen similar drain at internet.

 

[r32190]

I managed to supplement the 12V battery with an external power supply, with slightly higher voltage. It only provides less than 2A after ignition cycle.
Which module provides the current rating at Leafspy pro?

 

[woeful]

Which module provides the current rating at Leafspy pro?

Almost certainly the power delivery module, PDM. That will be measuring its own output to 12V, rather than the battery charge or discharge current (the difference being the car's 12V loads, being lights, electronics, fans, etc).

 

[nlspace]

Have you noticed any issues with brake pedal travel, or any strange noises under the hood when pressing the brakes?
The DTCs are indicating that regen is being limited due to some issue in the brakes/ABS. The brake master cylinder is driven by an electric motor driven actuator that has been reported by others to sometimes have corrosion issues. Also the power for this actuator is from the 12V system and a backup capacitor bank.

 

[James Pollock]

I managed to supplement the 12V battery with an external power supply, with slightly higher voltage. It only provides less than 2A after ignition cycle.
Which module provides the current rating at Leafspy pro?

LeafSpy reads the 12v battery amps from the VCM. Here is what the Service manual says about how the VCM determines that value. (There are three wires from the current sensor on the battery's negative terminal to the VCM on my 2011 Leaf.)

BATTERY CURRENT SENSOR
The battery current sensor is installed to the negative cable of the
battery. The battery current sensor detects the battery charge/discharge
current and transmits signals to VCM. VCM judges the battery
load based on these signals and controls the power generation
by converting the target generation voltage to a power generation
command signal and transmitting it to the DC/DC converter.

 

[r32190]

Almost certainly the power delivery module, PDM. That will be measuring its own output to 12V, rather than the battery charge or discharge current (the difference being the car's 12V loads, being lights, electronics, fans, etc).

Thanks. Query: If the PDM demands more than the 12V can provide, does it mean the HV battery is helping over DC-DC? AC compressor/HV charging/12V charging are not working.

 

[r32190]

Have you noticed any issues with brake pedal travel, or any strange noises under the hood when pressing the brakes?
The DTCs are indicating that regen is being limited due to some issue in the brakes/ABS. The brake master cylinder is driven by an electric motor driven actuator that has been reported by others to sometimes have corrosion issues. Also the power for this actuator is from the 12V system and a backup capacitor bank.

Unfortunately, EV cannot move. Cannot shift gear. That's the reason I unloaded the HV battery, tough process.
No weird sound when statically pressing the brake.

 

[r32190]

LeafSpy reads the 12v battery amps from the VCM. Here is what the Service manual says about how the VCM determines that value. (There are three wires from the current sensor on the battery's negative terminal to the VCM on my 2011 Leaf.)

Thanks for your info. VCM controls the HV relays and I can hear the 2 to 3 "click" sound after ignition cycle. I heard 2, my friend said 3. 3 is normal, +, -, precharge. Of course, it cannot be ruled out for causing problem at this moment.

 

[nlspace]

Is the 12V battery getting charged by the car or is it getting drained?

7 Amps on the 12V supply is not an issue, turn on the headlamps and the current will go even higher. But if the DC/DC output never jumps up to 14V, then the battery is not being charged and will drain the 12V battery

Try to get another reading of DTCs, the codes will help troubleshooting.

The car will charge using AC ?
The car will charge using DC ?
The car will START and go to READY mode?


If the answer is No to any of these then there will be DTCs and warning lamps on the instrument cluster; please describe any that you see.

The main contactor order: - , precharge, +

If you are only hearing 2 clacks and getting no HV inside the PDM, then suspect a bad contactor inside the HV pack. That would explain no HV for the A/C compressor and no DC/DC charging.

The car needs to be charging or in READY for the DC/DC to be operating.

 

[r32190]

Is the 12V battery getting charged by the car or is it getting drained?

7 Amps on the 12V supply is not an issue, turn on the headlamps and the current will go even higher. But if the DC/DC output never jumps up to 14V, then the battery is not being charged and will drain the 12V battery

Try to get another reading of DTCs, the codes will help troubleshooting.

The car will charge using AC ?
The car will charge using DC ?
The car will START and go to READY mode?


If the answer is No to any of these then there will be DTCs and warning lamps on the instrument cluster; please describe any that you see.

The main contactor order: - , precharge, +

If you are only hearing 2 clacks and getting no HV inside the PDM, then suspect a bad contactor inside the HV pack. That would explain no HV for the A/C compressor and no DC/DC charging.

The car needs to be charging or in READY for the DC/DC to be operating.

I disconnected the 12v battery since the issue happended. Drained 12V would not cause the problem. I recharged it slightly externally before any experiment.
The car will charge using AC ? No.
The car will charge using DC ? Unable to test.
The car will START and go to READY mode? Cannot shift gear from N/P to D. I suppose it is not ready.

I recorded the hi-low going edges of precharge relay trigger with scope, HV should be ready. See attached photo.

 

[cornbinder89]

Looks like you have inverter/PDM problem and codes. No 12 volt playing around will solve that.
Chase down the DTC one at a time.

 

[r32190]

According to 2011 leaf document, I cannot find "PDM", instead, I found IPDM E/R, intelligent power distribution module engine room. It has relays and fuses which is upside down, difficult to reach internal stuff with cable limiting the movement. I blown up the VCM fuse when probing HV control siganls and aware this box. There is a "CPU" at the block diagram but should not be inside that box.
Regarding the inverter, I checked the input capacitance, which is 1mF and 10kohm discharge resistance by unplugging the HV connector. Cannot verify other functionality.

 

[cornbinder89]

You didn't state the year, 11, and 12 don't have a PDM, the 13 and up do, all still considered Ze0. An important lesson on why year is necessary not just "model".
Just because you can't verify doesn't mean it isn't the problem.
360-400 volts DC is nothing to play around with.
Down load the service manual and follow the logic tree to solve the DTC's.
This in not a minor problem to diagnose nor fix.

 

[nlspace]

Please verify which model year is this car?

If it doesn't have a PDM, then it uses a High Voltage Junction Box, HVJB, aka DCDCJB, located between the motor/inverter and the firewall. Nearly impossible to reach without dismantling, but it is just a big dumb box with contactors and buss bars for routing HV, plus it contains the DC/DC converter.

 

[r32190]

I have this inverter. So I suppose it is very tough work to reach the junction box.
I am a veteran from semiconductor industry, not good doing this task. BTW, what is the typical 12V idle current drain? 13x7 = 91W is a huge consumption doing nothing, it seems eye catching to a semiconductor veteran, this can run several modern computers.

 

[nlspace]

Put a current probe on the 12V negative cable, or use Laef Spi to monitor the current, then start pulling the fuses listed on the left hand side of the diagram above to find which circuits are drawing current.

Do you have daytime running lights when the key is on and car in READY mode? Try that fuse also.

There is another trick to reading current by measuring the mV drop across the fuse, but may not be very useful for such a low current, need a really good meter too, see the chart from powerprobe website,
fuse voltage drop chart

You can find manuals for the sections called out for the DTCs at nicoclub website.

 

[cornbinder89]

Problem with "pulling fuses" on most newer cars, is when the fuse is replaced, the module attached goes through a start-up, drawing current for a while, and communicating on the CAN bus.
It can leave you chasing your tail, causing more "temporary" draws while looking for the one that will not shut off.
In the 2015 Nissan manual, it says 50ma is the limit for "dark draw" when the car has been sitting for about 10 min with NOTHING disconnected or re-connected, so everything should be in power down sleep mode.

 

[r32190]

Got this tester and thermal imaging gadget, mostly below 1A for all 20A fuse candidates. Thermal imaging cannot reach corners, the probe is integrated with the display. Only warm relay (35C) can be found at the top. Running out of idea

 

[cornbinder89]

Since you have to pull the fuse to plug in the device, you run the risk of chasing your tail when things on that fuse have to "initialize" on power-up.
You really want to be able to test without EVER powering down ANYTHING.
There are a number of ways to do that, how you do it is up to you, but not breaking power is the key.

 

[nlspace]

Only warm relay (35C) can be found at the top.

which relay? need a picture or reference designator.

pull the relay and see if the current drops.