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OK, The last time I hooked up my ECU through the CAN bus it caused a communication fault throgh the CAN bus and this kicked out the PSM and ABS. Now when I connected it, it caused the faults the first time I did it but hasn't since.

So, this is not a reliable way to drop PSM on the car while at the track (at least on dry days). Rick Gilhart and others, can you simply pull the fuse or how else can I disable the system. I would love to dump PSM and keep ABS but I don't think I can do that. Help!

Premier Motorsp

CC said:

I would love to dump PSM and keep ABS but I don't think I can do that. Help!



I think the easiest way to do this is going to be to call up Porsche Motorsport and order:

1 996.355.049.92

That is the 996 Cup ABS ECU/Hydro unit. Then you will probably need to do some rewiring to eliminate the PSM interfaces.

The wiring may be the complex part but I sure it is doable. You could use a GT3 front harness if the modifications to the stock harness got out of hand.

It is really too bad that Porsche/Bosch does not have available a motorsport control unit for the PSM. That would be really amazing.

Chris Cervelli
Premier Motorsports

Z-man

Tim:
Your dilemma is one of the reasons why I don't have a 996/997 or 986/987 for track use. IIRC, the latest versions of PSM cannot be completely defeated. I prefer to drive my car instead of letting a computer drive it for me.

Plus a $100,000 GT3 is about $90,000 more than I can afford right now for a toy!

And well, my MAIN reason for the lack of a newer P-car in my garage has something to do with a new kitchen I've been promising Mrs. Z-man. For the last 3 years...

Haven't really helped you much here - but with your knack for electronics, you'll come up with an eloquent solution. (I remember your video game seat project... )

-Z.

930man

i wish you could disable psm on the track this weekend my 997 kept having a psm failure on the car. i assume because the new lowered pss9 shocks. maybe i just over worked the thing lol

924RACR

I told you before - disable the steering angle sensor.

924RACR

Actually, you probably want to keep the steering angle sensor plugged in for your data acq, right? In that case, you would be better off failing the yaw rate or lateral G sensor. Do you know where these are located in your car?

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Vaughan: I don't get steering so that should be great. Have you done this? How do I try it?

Premier Motorsp

Vaughn,

So if onlyy the steering angle, yaw rate, or Lat G sensor fails the PSM turns off and leaves ABS intact?

Chris Cervelli
Premier Motorsports

930man

you think if shocks were lowered on a 997 tires were slightly different in height ... would that send a fault to the psm failure

ColorChange

no the lowering should have no effect

Gilhart 54

Tim,

I was told by many that my car would go into limp mode when disconnecting the PSM by removing fuses, it never has. I've tested disconnecting the PSM in stages. I've pulled fuses and taken my street X50 TT out for a ride in the rain trying to induce all sorts of slippery situations in which my car should go into limp mode, it never did. I've sinced removed all sensors from the race car because they're no longer needed and just add weight.

As you mentioned the ABS goes as well. I've asked many different people including WCGT driver Mark L. with his TT and believe he removed the wiring harness from the car and stripped out the wires that pertained to the PSM leaving the ABS intact. Mark tells me that his stock TT ABS is a PITA because it is not set up(proportioned properly etc.) compared to that of a Cup car.(What Chris said)

I would maybe try what some of the guys are mentioning above. Let me know what you find out. I can tell you that going to the dual master cylinder has made all the difference in my car. It's pretty hard to lock up the brakes on my car as the brake booster has been ditched as well.

Heading to Putnam tomorrow...

Rick

924RACR

930man - it's the tire size difference, that can most certainly mess with PSM. You're likely setting a wheel speed sensor fault or two. You'll need to be consistent with stock tire diameters if you wish to retain ABS functionality.

Disable the steering angle sensor - usually unplugging it is enough. Should be instant failure with the car on.

As for shutdown strategies, yes, all the systems I've worked on will go to what is being referred to here as "limp-home" - ABS and EBD function only, no TCS or ESC. YMMV, so you'd have to check your cars yourselves. Older systems or other manufacturers (non-Bosch) may not do the same...

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Vaughan: Where is the sensor?

924RACR

Usually on the steering column, under the dash. Look for a plastic thingy that the column passes through, with an electrical connector.

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Thanks Vaughan: I see it. Black plastic flimsyish thing that wraps around the steering shaft spline and has a wire running from it. How do you recommend I pull it? I have my manuals at home.