Roadster Sport will not stay in Performance Mode

[Roadster]

Bumping this thread as it was a fascinating read with widely varying results from knowledgable Roadster forum heavyweights culminating in a cliffhanger ending!

Hit the Performance mode, nice white letters. Punched it getting on the freeway, and it lasted about 3 seconds before going red... Turned white shortly after, so it did recover.

I was going to suggest that your PEM fan ducting might be leaking, preventing sufficient air from getting to the PEM, but I've already had mine weather stripped (fixing earlier problems), so that's probably not it. But I'm with you believing that this can't be right... I'll try using it more often, and see if I can figure out a correlation with something else.

@gregd, any further testing or observations here since you were experiencing the same results as the OP? Did you get any more intel from the SC?

I just ran my entire commute (27.8 miles this morning) in Performance Mode. 5-6 hard accelerations interspersed with highway travel between 65-90mph (more 70ish than anything else)...

Whenever I punched it I maxed out the 200kW output, and it stayed in Performance right up until I reached 80-90mph with occasional dropping out (red letters) at the very end. If it went red it recovered almost immediately once I stopped accelerating.

I didn't do a very good job of documenting any of above parameters, but I think this is enough to say that there is something wrong John.

@thefortunes, is P-Mode still performing as expected for you? Any chance you can document things in greater details for the next test?

With the Tesla, I can't take it to anyone other than Tesla and, worse yet, they don't really know how to work on it that well themselves.

If the sound of all of this is a bit scary; well it should be. Nobody owns an extremely rare exotic sports car without exposing themselves to major challenges keeping the thing running.

I'm really not interested in trying to diagnose problems myself. If I can't trust the manufacturer of the car to competently work on their own vehicle, then I clearly bought the wrong model.

It's not about *me* putting it in 'debug mode', or 'reading temps', or 'processing logs', that's the job of my mechanic.

@John W. Ratcliff, I totally get it. You want to enjoy the car in the same manner you did with your previous ICEmobiles and prefer not to deal with troubleshooting things yourself. The majority of high end supercar purchasers feel the same way so you're not alone with your sentiments. And, as evidenced by @thefortunes, clearly P-Mode does indeed work as intended on some cars. Now imagine if you paid the original $150K sticker for your 2.5 Sport and had this issue... and the same shrug of the shoulders from the Tesla techs! Something tells me you wouldn't take "that's just the way it is" as an acceptable answer. Then again, if this was 2011 again, you would have just purchased the car new, it would be under full warranty and you would have had the full attention of the service staff since this would have been their current flagship and it would be imperative to ensure you were a happy customer. Flash fwd to 2017... to say the spotlight has moved away from the Roadster is an understatement. In the end, you purchased a used, non-warrantied, discontinued model. That's where TMC comes in!

What the majority of the experts here are suggesting is that, while it's understandable to want to trust Tesla to diagnose the problem with their product properly, their sights are set higher at the moment so it's critical for the Roadster owner community to address the problems we encounter collectively. These are still rare and technologically nascent vehicles when compared to the Ferraris, Porsches and Bowties you mentioned which have decades of diagnostic maintenance history behind them for factory service techs to reference. More importantly, it's only fairly recent that Roadster owners have started to benefit from the trial & error successes that the home mechanic/electrical engineer/McGyver-esque-creative-problem-solving geniuses like @hcsharp, @wiztecy, @markwj and @gregd (to only name a few) have so graciously shared with us to address the problems the factory couldn't and, almost certainly never will, solve with a discontinued product line.

You posed a unique concern to the board so everyone's doing their part to help diagnose it. They're not asking you to be a mechanic; only to be intrinsically curious about helping solve the problem you posed. You tried the factory and got their response. If it's truly unequivocal in your eyes, take the blue pill. However, if you want to enjoy the car the way it was meant to be, the reality is it's going to be up to the good folks on this board to get P-Mode working for you again. And besides, pulling logs is a lot easier than pulling the heads on a car. Help them help you! In the words of @gregd...

To be fair, the service guys have probably done the same, but collectively we might have more hands-on experience than they do. Let us know what it says, and perhaps we can help steer them in a productive direction. No harm running this in parallel with their investigation, and we might all learn something in the process.

I expect (suspect) that any rare car will have its community of users, tinkerers, and professional mechanics. The Roadster is no different. Not all users are going to be tinkerers or mechanics, nor do they need to be, but they're part of the community none the less. Our community is here to support each other and the unique cars that we drive.

 

[gregd]

@gregd, any further testing or observations here since you were experiencing the same results as the OP? Did you get any more intel from the SC?

Not much news, other than I had a separate issue with 1146 errors (low fan speed) in the logs, mostly while charging, that the SC did some troubleshooting for. They found that there was a wiring error, or wiring change, related to the fans, and changed things to be proper. The result was a much reduced PEM running temperature. I suspect that I can run in Performance mode now, but forgot to try. Will give it a go next time I'm out on the freeway.

And, though reduced, it seems that the fan speed errors still persist. So perhaps my fans do need a replacement... Will check that out at the next service in a few months. Not worth the hassle to bring it in again now, as the car still drives just fine.

 

[S-2000 Roadster]

It seems that temperatures have been thoroughly discussed, but what about the battery charge?

I have a 2.5 non-Sport, and I only see Red some of the time with a full charge; and then only after flooring the accelerator at 100 mph. It recovers quickly and turns White, but only when the battery is well over half full.

I've noticed that if I drive the car to work and decide to try Performance mode in the evening, when the battery is down below the half-way point (I work about 40 minutes to an hour from home), then there are times when the display stays Red all the time. I have the impression that as the battery charge on my non-Sport drops low, it simply doesn't have the stored power for Performance mode.

In other words, my experience is anecdotal, but I suggest you try charging your battery full, probably in Performance charging mode, and then see how well Performance driving mode works.

It's sort of like filling the tank - even a sports car won't automatically fill the tank for you when it's empty. I realize it's not the same, since the battery isn't much more than half empty on mine when Performance starts to dwindle, but it's still an operator issue to some degree. The car does not perform exactly the same under all conditions. The Roadster happens to be a bit more finicky than mature sports cars.

 

[Kerios]

I had exactly the same issue following PEM Cooling fan issues, and this led to the PEM being replaced completely. I am certain it is down to the change of single PEM fans to the double setup which leads to the draw current being in excess of what the connector can handle and subsequent one see's degradation of the contacts (there is plenty on TMC relating to this). I mitigated the issue initially by replacing the PEM double fan unit, but nonetheless Tesla eventually concluded (though didn't admit) that the PEM needed replacing, once it was the transition of the performance mode to the white lettering was steady and it based on this morning's race to work I can certainly confirm that it remains extant as can the rather surprised Yamaha R1 rider who was left in the dust

I'd strongly recommend looking at the connectors for the PEM Fan unit and where possible those between PEM and connecting cable, I suspect the lack of cooling comes from the inability for the system to deliver the current needed to maintain cooling effectively.

 

[gregd]

I seem to be able to stay in performance mode now, after the "fan wiring error" was corrected. Still don't know exactly what that was, or if the current lower ambient temperatures are a significant factor, but it seems happy. I AM still seeing the 1146 errors in the log, however. That was evidently not fixed by the fan wiring change.

 

[DeedWest]

It seems that temperatures have been thoroughly discussed, but what about the battery charge?

I have a 2.5 non-Sport, and I only see Red some of the time with a full charge; and then only after flooring the accelerator at 100 mph. It recovers quickly and turns White, but only when the battery is well over half full.

I've noticed that if I drive the car to work and decide to try Performance mode in the evening, when the battery is down below the half-way point (I work about 40 minutes to an hour from home), then there are times when the display stays Red all the time. I have the impression that as the battery charge on my non-Sport drops low, it simply doesn't have the stored power for Performance mode.

The following is analyzed from my 2.5 Sport (#1438). I have personally learned a lot from driving in Debug Mode and analyzing the temperature behaviors when in different driving modes. Sorry in advance if some of this has already been mentioned in other ways.

What I've gathered, is that the car seems to always prioritize keeping the battery at optimal temperatures (which is common knowledge to most of us, yes), but seems to behave differently when in different modes. For example, when putting the car into Range Mode while driving, the PEM temperatures rise almost instantly. Most commonly, mine go from 37-38C right up past 41-42C when switching into Range Mode. Similarly, the Battery temperatures drop shortly after, as I'm assuming the PEM is working harder to keep the battery cooler in Range Mode. This was during a long 25 mile highway drive north back home to my house. 60-70 mph, mostly in Standard Mode, in 75 degree humid weather in Dallas. I cycled through the driving modes out of pure curiosity. Go figure.

When switching back to Standard or Performance Mode, the PEM temperatures gradually drop again and stay pretty consistent. They obviously gradually rise and lower when driving in certain situations, such as highway speeds, rapid accelerations, and regenerative breaking, but the consistencies sure are there. Performance Mode, as we know it to do, allows the battery to get hotter past the normal threshold noted above in earlier posts, which is why it's not always recommended. In cold weather, I use performance mode frequently, simply because I enjoy the torque curve and I've never seen the battery temperatures rise above 25C in the recent months. I usually limit use when it's hotter out, to avoid the battery getting warmer than it needs to, but alas, this is only my personal preference.

I have noticed that the PEM temperatures are higher when the battery is in the lower SOC, on days that I've driven further distances than usual. These raised temperatures are even after long periods of the car sitting in-between trips and charging cycles, so I don't believe it's solely from recent raised temperatures from driving.

That being said, I believe the cause for your car's behavior, @S-2000 Roadster, may be due to the car keeping the battery at optimal temperatures as the SOC reaches lower points. After all, that's what these cars do 24/7. It would only make sense that the PEM is working harder, regardless of driving mode, to keep your car's battery cooler when it's not as full, and more-so as it gets even lower. I know for a fact that ambient temperature and humidity both play a massive part on how the modes and the components' temperatures vary on drives. That alone can essentially ban Performance Mode from ever being in the white, and lower SOC's will fortify that.

I didn't realize the different modes changed the temperatures so drastically until just a month ago, so I'm thrilled to have learned something! That's the ultimate joy of these cars; the fact that we as owners are stewards of the Roadster's future and the continued growth of knowledge.

I am extremely confident that I will likely never drive another car, until there's a replacement, if any. I'd have 11 Roadsters before I'd consider something else, because nothing comes remotely close. It works for me, and if the day ever comes that Tesla stops supporting these incredible vehicles, that will motivate me even further to continue my own research and commitment to the supportive community that we have here.

 

[ML Auto]

From what I have seen Performance mode only lets the battery get warm when charging. The battery cooling activates at the same temp in standard or performance mode. There is really no reason not to drive in performance mode vs standard.

 

[DeedWest]

From what I have seen Performance mode only lets the battery get warm when charging. The battery cooling activates at the same temp in standard or performance mode. There is really no reason not to drive in performance mode vs standard.

In both 2.5 cars I've had, as well as a 1.5 Signature 100 that I drive very frequently from a friend, I've noticed the same behavior that I listed above. The car draws air conditioning from the battery at a certain point, but when I enter Performance Mode, it prolongs that feature even further. It appears to allow the battery to get hotter and raises the threshold of forced A/C cooling. In the 2.5, it seemed to me that the threshold was much higher in Standard Mode than in the 1.5, which is customary considering the 2.X PEM differences.
Could it be possible that different cars have different thresholds? Who knows...perhaps we've uncorked some new discrepancies that vary from car to car!

 

[strider]

I'd be curious to hear from @John W. Ratcliff now that it's winter time. As I stated I drove my car for 4.5 years in the Bay Area. When in Perf mode if I would stomp on it it would change to red then to back to white shortly after letting off the accelerator. Last July I move to Oklahoma. It's Africa-hot here. My car behaved just like John Ratcliff's. Even under very gentle driving the letters would go red before I left my driveway. As temps began to fall into Fall and winter the car works like it did in the Bay Area. Switch to red letters when stomping on it, back to white after letting off.

I contend that there is NOTHING wrong w/ John's car. He lives in a place that gets hot in the summer. The Roadster doesn't deal with heat very well. There were plenty of days where I would get ZERO cabin AC for my entire drive. It was shunting everything to the battery to keep it under 40C.

As for the launch counter, I suspect the SC was just conflating the Model S Launch counters.

 

[hcsharp]

DeedWest you might be confusing battery thermal management with PEM behavior. The PEM does nothing to control battery temps. Only the A/C system plays a part in battery thermal management, not the PEM. I've noticed different PEM temps in each mode but only if I drive differently. I'm curious if your observed differences in PEM temps in each mode exist even if you drive the same.

 

[DeedWest]

The observations I made on PEM behavior were while cruising at a consistent highway speed and changing the driving mode. After the highway, I tried the same test again on a 40mph stretch of road, and saw the same results. It was interesting to say the least, as I'd never thought anything of it. That's probably what made me come to the uneducated conclusion that the PEM had something to do with the battery behavior. I'm aware that the PEM converts DC from the battery to AC needed for the motor, so I've always assumed the PEM was linked to the battery's temperatures in SOME way, but it's nice to learn that it doesn't! Thanks for the clarification, @hcsharp!

 

[John W. Ratcliff]

I don't drive my car much in the winter, but when I have the performance mode doesn't go red ...as easily. It still does it if I repeatedly get on it, but it's not immediate.

I've decided to just not worry about it for now. If things continue to go well for me financially (go bitcoin!), I'm strongly considering getting the 3.0 battery upgrade.