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986 Boxster In Limp Mode

 
  #1  
Old 07-04-2019, 06:21 AM
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Angry 986 Boxster In Limp Mode

My 2000 Boxster roadster with 2.7 is in limp mode. I have a P1502 code

My generic scanner say is it is "fuel pump relay end stage. I have read where it is actually "jacking spring" issue
If I clear the code, the engine smooths out and runs correctly
I have removed the throttle body, cleaned it and reinstalled. Problem remains.
The problem remains even after installing another throttle body,
I cleared the codes, recalibrated the throttle body by turning on ignition for 60 seconds(without touching the gas pedal), turning ignition off for at least 10 seconds, then turning the ignition back on, P1502 code reappears

I would really appreciate any advice on how I can get back on the road!

-Is the throttle body the problem?
If not, where should I look?
If the TB is bad, is it OK to try a used one or an aftermarket TB

Thank you

Bob
Nashville, TN area
 
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Old 07-12-2019, 02:59 PM
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P1502 Throttle Jacking Unit, Spring Test – Above Limit

Possible faults:

- Throttle return time too long.

Maybe the throttle is really dirty. Try cleaning the throttle jacking unit and the throttle body well with a residue free cleaner. I like an electronic cleaner that comes in an aerosol can. I do not suggest you disassemble the housing and clean in the electronics just the exterior hardware and the buttterfly valve and throttle body.

Also, what I recall is clear the codes. Then do a throttle/eGas calibration operation. Then check for any throttle/eGas error codes. Depending upon what if any codes you get the throttle control may need to be replaced.
 
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Old 07-13-2019, 08:24 AM
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Originally Posted by macster View Post
p1502 throttle jacking unit, spring test above limit

possible faults:

- throttle return time too long.

Maybe the throttle is really dirty. Try cleaning the throttle jacking unit and the throttle body well with a residue free cleaner. I like an electronic cleaner that comes in an aerosol can. I do not suggest you disassemble the housing and clean in the electronics just the exterior hardware and the buttterfly valve and throttle body.

Also, what i recall is clear the codes. Then do a throttle/egas calibration operation. Then check for any throttle/egas error codes. Depending upon what if any codes you get the throttle control may need to be replaced.
thank you for the reply
i removed the throttle body a few weeks ago. It was remarkably clean. I still cleaned it. I opened the butterfly while doing the cleaning. Could this have caused any problems with the jacking unit?
 
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Old 07-13-2019, 08:33 AM
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thank you for the reply
i removed the throttle body a few weeks ago. It was remarkably clean. I still cleaned it. I opened the butterfly while doing the cleaning. Could this have caused any problems with the jacking unit?
 
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Old 07-14-2019, 07:53 AM
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2000 Porsche Boxster, 2.7 engine, 5 speed, 73K miles

Symptoms: car in limp mode, pending P1502 code, car runs fine once the code is cleared, code returns as soon as the car is restarted, I have installed 2 other throttle bodies, the problem remails

Could my problem be related to an issue with the accelerator and the communication with the throttle body?
 
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Old 07-14-2019, 08:21 AM
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Originally Posted by pcsbob View Post
thank you for the reply
i removed the throttle body a few weeks ago. It was remarkably clean. I still cleaned it. I opened the butterfly while doing the cleaning. Could this have caused any problems with the jacking unit?
Did the code appear, did the limp mode appear, after you cleaned the throttle body and opened the butterfly valve? Did the valve require force to open?

(I had the throttle body off my 2002 Boxster at least once that I can recall -- when trying to identify the source of some symptoms that proved to be a bad AOS -- and cleaned it. It was dirty the butterfly valve in fact was wet with oil - which didn't register with me right away -- but I never forced open the valve. The valve and the TB cleaned up real nice with just me spraying all the surfaces down with the aerosol electronics cleaner.)

Have you tried a throttle calibration operation?

What I recall from my Boxtster OBD2 references is to first clear the codes (do the clear even if there are no codes, the CEL is off). Next perform a throttle/eGas calibration, then check for any eGas error codes after. If there are any then address the problems they indicate which really just means replace the unit. There are no user serviceable items in the assembly.
 
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Old 07-14-2019, 10:01 AM
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Thank you for replying!

Did the code appear?
Yes, the code came back as soon as the ignition was switched on again

Did the limp mode appear, after you cleaned the throttle body and opened the butterfly valve?
Yes, limp mode reappeared as soon as the car was restarted.

Did the valve require force to open?
Yes, the butterfly did require force to open, It would close as soon as I released it.

I did more research and found that the "egas" throttle system has a potentiometer connected to the gas pedal. I thought there may be a problem there.

I can clear the code will the car is running. The rough idle will smooth out, the car will then accelerate normally. Turn the car off, turn the ignition back on and the P1502 code is in a pending status and the car will not go over about 1800-2000 rpms
 
 
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