Rear motor not operating 45 min after charge!

1401 Views 28 Replies 9 Participants Last post by wesleyorama, 4 h ago

Noreaster

Discussion Starter · 15 d ago (Edited)

I am more than halfway into a 2,200 mile trip with a 5 month old 2023 I5, just passed the 5k mile mark. Beginning yesterday I noticed while on cruse control the car would lurch forward to compensate for being 2-3 mph under the cruse set point. Today I figured out the rear motor was no longer operating, the lurch was the delay until the front motor took over.

Today I charged 3 times for +/-30 min each. Then driving 70 mph for ~45 min all is normal car drives fine (no lurching). After 45 min of driving at 70 mph, the rear motor ceases to function, I then enable SNOW mode (constant AWD) to prevent lurching. (Image shows front motor doing all the work, rear shows a single bar but ODB2 reports zero)

Checked ODB2, no stored DTC's. The rear motor torque that was ranging between -8 & 35 during the 45 min after the charge, then torque is a constant zero.

Anybody know of a service bulletin that addresses this issue?

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croldan72

· #2 · 15 d ago

Are you in snow mode?

I get what you are saying, just looks really odd, with the 77 degree outdoor temp!

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ska bob

· #3 · 15 d ago

Sport mode will also keep both motors engaged. Almost sounds like the rear motor is over heating and it's limiting power to it, going around 70mph shouldn't be any issue for it. Or it may be a bad motor temp sensor giving false readings. I would use your obd2 app to monitor temperature and see if it's reporting anything funny and it will likely need to goto the dealer. Haven't heard of that happening before and no TSBs listed for the motor, just battery preconditioning and charging issues.

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Murry

· #4 · 15 d ago

That's very, very interesting.

Do you happen to know what was the exact type of the fast chargers you have used? Were they 800V or 400V?

My theory is that if it was on 400V chargers (including Tesla Supercharger), it's possible that the rear motor or inverter overheated as it's actually the device that's converting from 400V to 800V at maximum capacity.

On the ODB2 reader, have you checked the drivetrain temperatures by any chance?

Noreaster

Discussion Starter · #5 · 15 d ago

I just checked the motor temp before driving this morning, it's reporting 72° which is 10° higher than ambient. I noted the motor temp at the time the rear motor quit yesterday, it was 212°. I did not see a significant reduction in that temp as I continued to drive. I'll watch it closer today.

Thanks for taking time to consider my issue and replying.

ska bob said:
Sport mode will also keep both motors engaged. Almost sounds like the rear motor is over heating and it's limiting power to it, going around 70mph shouldn't be any issue for it. Or it may be a bad motor temp sensor giving false readings. I would use your obd2 app to monitor temperature and see if it's reporting anything funny and it will likely need to goto the dealer. Haven't heard of that happening before and no TSBs listed for the motor, just battery preconditioning and charging issues.

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Noreaster

Discussion Starter · #6 · 15 d ago

The issue occurs 45-50 min after charging. I've been using EA chargers exclusively, and apparently they are limiting output to <150kW at thus time.

With regard to the torque the ODB2 reader I'm using does not appear to recognize the front drive motor (I'm open to recommendations for a better app), not sure about which motor temp the app is reading, but it was reporting 212° when the rear motor quit.

Thanks for reading & replying to my issue. We are all smarter together!

Murry said:
That's very, very interesting.

Do you happen to know what was the exact type of the fast chargers you have used? Were they 800V or 400V?

My theory is that if it was on 400V chargers (including Tesla Supercharger), it's possible that the rear motor or inverter overheated as it's actually the device that's converting from 400V to 800V at maximum capacity.

On the ODB2 reader, have you checked the drivetrain temperatures by any chance?

Noreaster

Discussion Starter · #7 · 14 d ago

The motor temp is not what I expected. At my first stop to charge, I'd not traveled far enough to lose the rear motor, motor temp was under 200°, but during charging at around 100kW, the temp rose to over 200°. After driving only about 20 min, the rear motor quit with the temp at 215°. While continuing to cruse at 80 mph (Oklahoma hwy 44 speed limit), the motor temp continued to climb another 15°. Charging now at 150kW, motor temp up to 240°.

Mikael48

· #8 · 14 d ago (Edited)

One of the screens in Car Scanner Elm Obd2 shows the electric oil pump (EOP) commanded/actual RPM - this pump cools the rear motor. Also check other temperatures: inverter, coolant 1, coolant 2, etc.

HKtech

· #9 · 14 d ago

Subscribed.

Noreaster

Discussion Starter · #10 · 14 d ago

6

Here are some ODB2 readings captured while the rear motor is not working.

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ska bob

· #11 · 14 d ago

I've never checked my motor temp while on the freeway so I don't know if 212+ is normal. I did find this on a website, 90-95C would be under about 200F so it seems it may be getting to hot.

- EV motors are no different from the engines of ICE vehicles -- they have many components working seamlessly together. And more importantly, they get hot when in use.

Like an ICE engine, an EV motor needs to be kept within a certain temperature range to run efficiently -- between 90-95 ℃. Going beyond that range in an EV causes overheating, during which the engine may run inefficiently or enter safe mode.

Install electric vehicle temperature sensors to monitor:

Electric motor oil temperature
Electric motor winding temperature
Electric motor coolant temperature

Electric motor temperature control isn’t strictly about keeping temperatures down. In colder climates, motor temperatures need to be brought up to around 15 ℃ before driving for efficient operation.

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BigMo

· #12 · 14 d ago

Curious as well.

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HKtech

· #13 · 14 d ago

Noreaster said:
Here are some ODB2 readings captured while the rear motor is not working. View attachment 50000
View attachment 49997
View attachment 49998
View attachment 50001
View attachment 49999
View attachment 49996

When you experience this temperature on RWD propulsion unit stator temperature....
Are you pulling trailer
Are going over long incline for more than 10 miles
What is additional weight you have in the vehicle.
Was the battery management active for getting HV DC pack up to temperature

Noreaster

Discussion Starter · #14 · 14 d ago

HKtech said:
When you experience this temperature on RWD propulsion unit stator temperature....
Are you pulling trailer
Are going over long incline for more than 10 miles
What is additional weight you have in the vehicle.
Was the battery management active for getting HV DC pack up to temperature

Driving with normal luggage & 2 ppl. No trailer, no excessive speed, 75mph 90% of the time.

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HKtech

· #15 · 14 d ago

Noreaster said:
Driving with normal luggage & 2 ppl. No trailer, no excessive speed, 75mph 90% of the time.

How long inclines you had when this started happening.....
What was percentage RWD vs FWD....by using carscanner app before FWD was actively managing propulsion?

HKtech

· #16 · 14 d ago

I do know that most of pids for Hyundai EV platform was donated by some German engineer.... that does this as hobby on all vehicles he get chance to collect data.
Motor pid temperature is under question is really Motor stator temperature or pid that is showing estimated rotor temperature from other sensors.
And if by mistake carscanner developers had it set wrong formula or name for this pid.

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HKtech

· #17 · 14 d ago

I will test it out on my 2023 Ioniq 6 when I get the chance and see if factory scanner is showing same value as carscanner app.
My bets is that this pid is for E-machine rotor calculated temperature ( there is no real temperature sensor, it is calculated by other sensors data

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Noreaster

Discussion Starter · #18 · 14 d ago

HKtech said:
How long inclines you had when this started happening.....
What was percentage RWD vs FWD....by using carscanner app before FWD was actively managing propulsion?

The RWD quits after about 45 min of driving at highway speeds. If I stop & charge for 30 min, RWD is restored, for about 45 min (sometimes less if the stop was shorter.)
I'm driving in normal mode until RWD quits (all seems normal at this point), then enable Snow mode (just to avoid the lurch, apparently caused by the car waiting for RWD for a second before enabling FWD).

Mikael48

· #19 · 14 d ago

This screen shows the Electric Oil Pump rear motor EOP Actual Speed 0 rpm.
You should bring up the EOP Commanded Speed, by clicking 2x on any other less relevant box (Batt Min etc.) and selecting [MCU] EOP Commanded Speed. Then you will see if the Electric Oil Pump works as expected.

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Noreaster

Discussion Starter · #20 · 13 d ago

Got it EOP Command Speed. 0 when stopped, ~1900 when RWD working & moving. I'll update when RWD quits.

Thanks for the suggestion!

Mikael48 said:
This screen shows the Electric Oil Pump rear motor EOP Actual Speed 0 rpm.
You should bring up the EOP Commanded Speed, by clicking 2x on any other less relevant box (Batt Min etc.) and selecting [MCU] EOP Commanded Speed. Then you will see if the Electric Oil Pump works as expected.

View attachment 50005

Following is screen shot of EOP Command Speed after RWD quit.

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Mikael48 said:
This screen shows the Electric Oil Pump rear motor EOP Actual Speed 0 rpm.
You should bring up the EOP Commanded Speed, by clicking 2x on any other less relevant box (Batt Min etc.) and selecting [MCU] EOP Commanded Speed. Then you will see if the Electric Oil Pump works as expected.

View attachment 50005

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