Reduced Engine Power - limted to 11mph

[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.

[BobX]

I don't think its a low voltage issue as I've fully charged the batter using a trickle charger. The vehicle starts up fine now. But I set the fault at most key ups. As for intake blockage I don't thinkin should set s P1502 based on the description. Based on what I read above, the throttle is not returning to default position fast enough during a learn. After i clear codes while vehicle.is running, everything runs great. I even monitor the throttle position using the scan tool and it reads likely values. I guess I will try to replace the aforementioned part and see hoe it goes. Thanks for all the suggestions.

[Jager]

I'm really curious to know what the voltage is while the car is not running. It's possible to start the car with lower than optimal voltage. Then when the car starts the alternator kicks-in and provides higher, more than sufficient, voltage. Do you have a volt meter?

[BobX]

I've tried with the battery charger hooked up which should have more than enough juice to pass any diagnostic. But I'll check the battery voltage once I get my voltmeter home from work. As for the throttle position sensor replacement, has there been other failures? Should i replace the entire throttle body instead? I've been driving this thing all weekend and every time except once, failed P1502. Once I clear codes it runs great for that key cycle. One more question, is the throttle body easy to get to?
Thanks.

[mikefocke]

as in pedrosgarage.com has an article on cleaning the throttle body which would help you locate it and tell you what the parts of it are. Anything chew any wires?

[jhandy]

replace the throttle body??!!?
no way.
go here for a picture of the sensor.
http://www.theautopartsshop.com/auto+car-usa+parts/porsche+boxster+throttle-position-sensor.html

it is two bolts and a plug. follow the air intake tube from the air filter to the motor.
Where the plastic tube meets the motor is the location of the throttle.. look on the side of the throttle body to find the sensor. I would take it off and spray some electrical cleaner into it. Because it is a mechanical spring, it may just be gummed up.