Reduced Engine Power - limted to 11mph

[BobX]

Well, the check engine light finally came on. I still cannot "learn the egas". I even tried disconnecting battery just to see if I can get it to learn. No success. I'm going to try to pull codes next. Is there a history of sensor failure in these cars? I did try to crank the engine with a low battery, but I can't imagine that failing accelerator pedal sensors. Anyone know what else I can try before taking it in?

[Paul]

Status please.

[BobX]

Finally got a code reader hooked up and saw a P1502 Pending. When I clear codes while the vehicle is running, the car runs like there is nothing wrong. Reading codes after clear codes, there are no faults active or pending. But on the following start, it will go back into reduced power mode and have P1502 Pending. Based on what I've learned so far, it won't learn "egas" and it is failing some throttle code during key up. However, I think it's failing falsely as once the code is cleared, the vehicle runs flawlessly. Not really sure what to do at this point. And thanks for the followup, Paul.
Any help would be appreciated.

Robert

[Jager]

What is the voltage reading on your battery when the car is not running?

[Paul]

Just to rule this out, check the intake plumbing from the air cleaner to the MAF to the throttle body for air leaks.

[urban_legend]

If you could use some help or a referral to a good indy p-car shop just PM me.

The sad part of MI is good Boxster weather is flying by.

[jhandy]

so the way I understand the problem is that the car is stuck in "limp home mode".

there is a electric throttle valve switch on the side of the throttle body. It may be loose or a poor connection, or maybe failed altogether.

unless you charged the battery while it was still connected to the car, I cant see how the charging of the battery could have damaged the switch. May be coincidence.
looks like a square with two nuts on each wing, and a plug in the bottom.
If you know how to use a multimeter, you may be able to test it.


2000 Porsche Boxster F6-2.7L
Vehicle Level Powertrain Management Computers and Control Systems Testing and Inspection Diagnostic
Trouble Code Tests and Associated Procedures P Code Charts P1502
P1502 Notes P1502
412 Throttle Jacking Unit, Spring Test - Above Limit

Function
The position of the throttle is controlled by a digital position controller which emits a pulse-width-modulated (PWM) duty cycle and a direction bit.
After the output stage has been deactivated, the throttle is brought into emergency air position by means of two springs. This return of the throttle must take place within a certain time. If this time is exceeded, a fault is stored in the memory.

Diagnosis conditions
Ignition on (approx.30 sec. )
Stationary vehicle
Engine not running
Engine temperature> 5 °C
Intake air temperature> 5 °C




In any case, part number 99660611600. 4$ from china, 97$ generic replacement, 161$ from porsche.