VII7

If you belive the PSM is malfunctioning try turning it off (hold the PSM button for 3 seconds).

asellus

If the yellow light on the tachometer gauge is flashing during hard cornering then that is PSM intervening to keep the car on track. There is a perceived loss of traction or mismatch of steering angle versus yaw and the car is actively stepping in to correct that.

If you're still running them at 45 PSI, drop your tire pressures to the comfort level and see if that changes the behaviour to be more in line with what you expect.

Tomasphil

Ok, the latest, I took the 911 to DeJung Motorsports, & Steve DeJung, the owner & mechanic. I explained the issue that even w the 2nd set of new tires, the PSM warning light still blinks on tight cornering. He hooked up a Porsche diagnostic device, the size of a PC, to the car. He found no "active" faults - just "passive" or old ones. He drove the car for 10 minutes, on the freeway and back to the shop. He had no issues, the warning light didn't come one. He told me to drive it for a few weeks, especially on the Bohemian Hwy, an 8 mile stretch, of hills & dips, & tight corners. I did that, and of course the yellow PSM warning light came on 10 or 15 times. I'm only in the curve for 4 or 5 seconds, with the light blinking, but I never felt that anything of a PSM nature was intervening, like slowing the car down. The car drove well. I finally quit paying attention to the warning light, as it requires taking my eyes off the road, and slowing down, for caution. Not paying attention to the light, I was able to corner with more confidence. It took a bit getting used to. With this car, a 911 SCab, I can approach a curve with a grade change, at 45 or 50, and not worry - the car cuts right through it.

When I got on a road with higher speeds and more level, the corners were more gradual, the grades more gentle, and the yellow PSM light never came on.

I'm wondering if the PSM light comes on like some automatic warning light, or does it indicate some issue?

Levy

i've got the same 2013 C2S (but a coupe). have never seen my PSM light come on or blink unless i approach max grip/the point of no return. nothing normal about what's happening with your car. something is not right but i have no idea what it could be other then the few suggestions already made. use to run high tire pressures in my car (40/43) and still never encountered what you're seeing. decided lower pressure worked better for me with the nicer ride quality on city streets so now i'm usually 31/34 or somewhere close to that. have been running oem P zero's my entire time of ownership

good luck getting things sorted out

Noah Fect

Sounds like there's a misbehaving yaw sensor or steering angle sensor. Running 45 PSI is goofy, but even so, tires will not cause this.

Tomasphil

Continuing this dialog about the yellow PSM warning light coming on while cornering: DeJung Motorsports, the local Porsche shop for maintenance, hooked the car up to a diagnostic system a few weeks ago. First they cleared the system. I drove it for a month, and returned. DeJung said there were faults in the gateway system. Dejung recommended I take it to Marin Porsche, as they have better diagnostic tools. I took it there for a diagnosis. Their report: they found "no faults on the system". They commented that "the tires are not N rated". They drove it 3 times, and couldn't get the yellow PSM warning light to come on, although it's been wet & drizzly. They reprogrammed the DME and transmission. The service guy said that many of his customers do not have N rated tires, and haven't had any issues with performance.

I drove the car home, and went around a tight hilly curve at 40 mph near my house, and the yellow PSM warning light came on, just as it had before. I made a U turn, to drive it again, and the warning light came on again. The dealer not finding anything, has left me wondering if there's an issue at all. Yet I've had this car for 5 years, advanced the odometer from 16k to 66k miles, and know the car well. I know the yellow PSM warning light didn't used to come on all the time, like it does not. The new rear tires are Continentals, like the old ones, and the same size. It is a mystery that the dealer didn't find any issues. At this point, the only option seems to be to get N rated tires. Any other suggestions?

Speed2k

I don't think it's the tires. Are you overdriving the car?

VII7

You should get a set of N rated cup tires (the 4 corners) that ought to do it.

991Targa4S

How much throttle are you applying when the Light comes on, and how much steering angle do you have applied?

Tomasphil

The light comes on when I'm going 40-45, in a tight corner. I don't know how to estimate the steering angle. Other cars in front of me, mini vans & Toyotas, are doing the same corner at the same speed. It's not excessive speed. It's a 90 degree turn in 200 ft or so, from beginning to end. The 911S should be able to do it wo a warning light coming on. I've started ignoring the light. Cuz when I start looking for it, I slow down... & hesitate... & glide thru it like I'm in my pickup, instead of a 911S. I'm beginning to think it's a technicality. I could spend $2k for a new set of N tires... but since the rear tires are new, my sense is I should drive them for 20 or 30k miles, then get all new N tires... when all 4 tires need to be replaced.

koala

I'm not sure what to say other than the PSM system is acting in the way you'd expect it to.

I have horrendous Bridgestone RE980 all-season tires on my 911 now as I decided to roll the dice and go for reduced road noise at the expense of dry grip (big mistake, these tires suck). I can get the PSM system to intervene very easily now, whereas when I had the P-Zero N0 tires, I very rarely had PSM intervene.

If you want to test this theory, turn off stability control and take the same corner. You're going to get even more wheel slip before the system intervenes (even when it's 'off' it's still on, it just has a higher threshold before intervening). Just exercise caution as the car will be more difficult to control if you go even further beyond the available grip for the specific situation.

asellus

The PSM light turning on/flashing means PSM is intervening, as mentioned numerous times before. That's what it's designed to do. The light is telling you that it's doing stuff. It doing stuff is not a problem with the system, it's a problem with the driver, the environment, or both.

Based on everything you've said, you are driving too fast or too rough for the conditions. Smooth out your inputs, slow down, and it'll stop saving you.

afk

im not sure I agree - OP states mini vans and Honda’s are going at the same rate

also he’s driven this car for many miles ... he knows how to drive it to his skills. - unless he just move from straight roads in TX or UT or KS to some twisty OR or CA location ?

lets please not discard his situation to bad driving.

afk

Btw I’m not saying there are no fun twisty round in TX or UT or KS - just trying to differentiate

Noah Fect

Yeah, that's BS. Something's clearly wrong with the car, but as usual, if it doesn't throw a code, the "factory-trained techs" are helpless. Might as well take it to a faith healer.