Leaf EM57 resolver wired to Johannes board — angle stuck at 0 in FOC

[Daajason]

Title:
Leaf EM57 resolver wired directly to Johannes board (RES pins) — angle stuck at 0°

System
Motor: Nissan Leaf EM57
Controller: OpenInverter Johannes Leaf board
Firmware: 5.xx.R-FOC

Resolver is connected directly to the RES_R1/R2/S1–S4 pins on the Johannes board (not routed through the OEM inverter PCB).

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Problem

Resolver angle shown in Spot Values remains 0° even when the shaft is rotated by hand.

FOC firmware is running and encmode is set to resolver.

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Resolver Connector Pinout


Small 8-pin resolver connector on the motor (not the wiring harness)

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				  Top
Away from Motor			1	5	Motor side	
				2	6
			clip	3	7	
				4	8
				Bottom

Internal pin wiring top top to bottom:

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top 1  2  3  4  5  7  8  9 bottom

Using continuity testing between the internal resolver terminal strip and the external connector I mapped the wires as follows:

• Pin 1 – Green
• Pin 2 – Blue
• Pin 3 – Red
• Pin 4 – Black
• Pin 5 – Yellow
• Pin 6 – White
• Pin 7 – Gray
• Pin 8 – Pink

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Coil Identification

Measured resistances with resolver disconnected:

• Red ↔ Pink = 10.6 Ω
• White ↔ Gray = 25 Ω
• Yellow ↔ Black = 25 Ω

Remaining wires:

• Green ↔ Blue = temperature sensor

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Current Wiring to Johannes Board

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RES_R1 → Red
RES_R2 → Pink

RES_S1 → White
RES_S2 → Gray

RES_S3 → Yellow
RES_S4 → Black

Temperature sensor wires (Green / Blue) are not connected to resolver pins.

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Firmware Settings

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encmode = Resolver
respolepairs = 4
pinswap = None

FOC firmware confirmed running.

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Measurements

Resolver connected.

Meter set to AC volts.

Across excitation pair:

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Red ↔ Pink ≈ 0V AC

Across signal coils:

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White ↔ Gray ≈ 0–0.1V AC
Yellow ↔ Black ≈ 0–0.1V AC

No change when rotating the shaft.

If I reference the meter to another resolver wire I can see some AC voltage, which suggests the excitation signal may be floating.

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Connector Verification

• Resolver connector fully seated and locked
• Continuity verified between internal resolver terminal strip and external connector pins
• Coil resistances verified multiple times

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Questions

• Should resolver excitation be measurable across RES_R1 ↔ RES_R2 with a standard multimeter?
• Is there any parameter required to enable resolver excitation beyond encmode = resolver?
• Is it expected that excitation may not be visible with a standard meter due to frequency?
• Is wiring directly to the RES pins supported, or must the resolver route through the inverter PCB?

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Attachments

Photos of:

• Resolver internal wiring
• Resolver connector pin mapping

[johu]

The inverter needs to be in run mode, i. e. set udcsw=0, cruisemode=Off, manualrun=On
Assuming no HV connected

Check for anything on lasterr

[Daajason]

Thanks so much for the quick response.

I don't have manualrun, but I did set manualstart = On after setting udcsw = 0 and cruisemode=off



After this, the angle shows about 150 degrees. But turning the shaft does not update it.

Here are my Spot values:



My friend ChatGPT is telling me that uexc == 0 means the resolver is not being excited.

[johu]

Don't trust your friend
uexc is the rotor excitation of non-PM motors (i.e. Zoe motor)
In run state you should definitely see resolver excitation

[Daajason]

I've found what is likely my problem, RES_S1 and RES_S4 appear to have a short on the board side.
Before I open up my inverter again I just want to verify that this is not the expected behavior. =)

[Daajason]

I opened up the inverter to get to the logic board.


There is a trace connecting pin 18 (RES_S4) and pin 20 (RES_S1).



There's a chance I've got the PIN mapping wrong, but I've scrutinized it so many times.
I've been using this layout: https://github.com/jsphuebner/inverter- ... f-gen2.txt

In the upper section where Pin 6 and 10 are, the row that has 2 pins is on the same plane as pin 18 and pin 20.

I must be missing something? Any help is greatly appreciated!

[jrbe]

https://openinverter.org/forum/viewtopi ... 171#p62171
S1/S4 I believe should be connected.

I think you need 5.3v, not 5.0v to get excitation, worth checking your voltage.

[Daajason]

Some more details:
My logic board shows Mini v1.1 if that makes any difference.

I re-watched the videos about identifying the exciter coil, and the other 2 coils. Then I systematically went through the SIN/COS coil combos to try to find which makes my angle change successfully.

The angle never changes while rotating. Different pin orientations have it at approx 45 degrees or 270 degrees, but nothing ever changes.

I am rotating the CV axles, not the motor shaft directly. The gear ratio is supposed to be around 8:1, so I'm making sure to turn them 10-20 times.
Is it possible the gearbox is spinning but the motor shaft isn't? I'm seeing both CV axles turn when I manually turn one axle.

Is it possible my R1 and R2 voltage isn't high enough to get the SIN/COS excitation needed? If so, how would I test this?
I have a cheap oscilloscope. Probing R1 and R2 shows 4.0 vpp. This is true both when i've disconnected it from the resolver and connected it. I thought there would be a small difference.

My dashboard is not showing any errors. I've connected HV and when I apply throttle, no errors. But no motor spin. I tried throttle in each SIN/COS pin configuration as well.

It seems like the logic board isn't getting a good read on the angle so it's not doing anything.

Any guidance is greatly appreciated. I've been working on it 5:30am-7:30am nearly every morning for the past week and feel like i'm really stuck on this.

[jrbe]

You will need one tire locked / on the ground, otherwise the open diff will allow the other side to turn to avoid turning the motor.