Yellow Electrical System Error - Service Required

[Scandinavian]

That's very interesting if the drive mode affects charging...don't understand that one!

Drive mode does not affect the charging but it seems Sport Plus mode brings more cooling to the battery when charging. I also think it might divert cooling from the cabin to help cooling battery instead.


Edited to say more cooling when charging!

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[chun]

Drive mode does not affect the charging but it seems Sport Plus mode brings more cooling to the battery. I also think it might divert cooling from the cabin to help cooling battery instead

All sport plus does to the battery is try to keep the battery at 35 degrees celsius. So if its hotter, it will cool it, if its colder, it will heat it; using max amount of energy. (Of course, it draws more power also for the motors)

It’s partly why range is crap in sport plus - quite an annoying oversight if you ask me, that you can’t be in sport plus without the car using max amount of energy to thermally manage thr battery.

 

[B61]

Well, I am not optimistic.

I won't know for sure until I talk to my advisor tomorrow, but I noticed them today charge the car to 100% today. I don't understand why they would do that, when I specifically explained that a low SoC is needed to reproduce the problem.

Maybe they did reproduce it, and fixed it, and did the deepest charge they could to see if it came back? (Best case scenario)

They charged mine to 100% as well… they were waiting for a red error… but it was yellow only, after they unplugged the car from the station…

 

[B61]

you making me paranoid now! I have never used fast charging on my car. Really haven't had the need. Now I will go try it out.

I haven’t used fast chargig during first three years at all.
During 4th year,,i was charging 4-5 times every month…up to 260kw….and then problems started.
First, with on board charger (22kw), then heater failed three times…then yellow error after every DC…ended with red error

 

[B61]

Derek, have you ever tried to switch to Sport Plus mode while sitting in the car as it’s charging?

If it is not too cool outside, that has done it for me . The car charges at 260 kW and the fans run like mad for a while. Try it to see if the fans spin up

Haven’t tried to switch yet… but i noticed that my J1.2 charge on 235kw only….during all charging process from 20-70% SOC. After 70%, it drops down to 200kw…
J1.1 charged over 260kw (up to 60%), then it went down slowly under 100kw (at 80%)

 

[B61]

Can the folks interested in this thread confirm something?

1. Do the fans spin up super loud during fast DC > 250kW?
2. Do the fans spin up when you put the car in Sport Plus?

I have a working theory that my issue is as simple as seized fans. I'm still working on draining the car so I can reproduce my issue again. In the meantime I've been using a lot of Sport Plus and do NOT notice fan spinup.

I can confirm #1…. Fans are very loud even at J1.2, when i charge at 235kw only.
Since i got 3phase in my summer house, i don’t charge on DC anymore, so i don’t ‘t have answer on #2.

 

[DerekS]

Dealer reports the fans are working as expected.

I was hoping for an easy to diagnose issue.

Tomorrow I drive with them to the charger to try and reproduce

 

[CrazyINP]

Dealer reports the fans are working as expected.

I was hoping for an easy to diagnose issue.

Tomorrow I drive with them to the charger to try and reproduce

Lets hope the guy comes with PIWIS attached and can detect the issue!

 

[DerekS]

Pretty successful outcome today.

The tech graciously spent time going to the charger with me. As most of us know there are three factors needed for optimum charging:
- low SoC
- Warmed battery
- Good charger

We arrived at the charger with only 9% SoC, but the battery temp was only 80F. Then the charger only dispensed 206kW. My heart sank thinking we wouldn’t hit the load conditions needed for the fault.

But then after a few minutes boom! Yellow electrical system error! And as an extra bonus it threw the red “park somewhere safe” error a few minutes later and stopped charging entirely.

We had to shut down the car for a few minutes before it would let us drive again.

Hopefully this caused enough logging to detect the fault and fix it at last.

 

[DerekS]

Any bets on what’s broken?

This is ChatGPT’s best guess.

Rank	Component	Likelihood	Why
1	Coolant pump (pump electronics or speed sensor)	70%	Fails instantly, no heat required. Classic signature.
2	Diverter valve (position implausible)	20%	Triggers exactly your errors, even cold.
3	Battery temp sensor (one of the NTCs)	10-15%	Instant flags, clears afterward.
4	HV charge controller	5%	Only if the above pass testing.
5	Battery modules	<1%	Behavior does not match.

 

[CrazyINP]

My bet is number 3! Let’s wait

 

[DerekS]

Diagnosis was none of the above!

“Needs battery isolator replacement.”

 

[Tooney]

Diagnosis was none of the above!

“Needs battery isolator replacement.”

I believe it is also called the "e-box". MSRP $4061 on sale online for only $3803.
Interesting because there was a TSB couple of years ago that told dealers not to replace only the e-box, need to replace the entire battery including the e-box.

This is the TSB: https://static.nhtsa.gov/odi/tsbs/2023/MC-10233932-0001.pdf
The guidance possibly just applies to the VINs in the original WNQ8 campaign.

 

[CrazyINP]

well, at least there were able to diagnose! Did they say how long would take to get your car back?

 

[DerekS]

well, at least there were able to diagnose! Did they say how long would take to get your car back?

The part should arrive next week.
I am much much happier now that we have it diagnosed.

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