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

 

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?

 

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?

 

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?

 

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.

 

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

 

As I mentioned before what I recall being offered in the Boxster OBD2 reference is to clear the codes, perform an eGas calibration then check for any error codes. I can't be 100% sure and I no longer have the references but pretty much the pedal and its electronics or the throttle body with its mechanical/electronics is not serviceable. Depending upon the error code one of these items would have to be replaced.

It is a long shot but you can do the eGas calibration and see if that helps. You in "forcing" open the butterfly valve while you may not have done any permanent harm the mechanism might be way out of calibration.

What I recall for this is with the key off and your foot off the gas pedal the whole time turn the key to on. Wait at least 60 seconds. Turn the key off for at least 10 seconds. The next time the engine is started -- and it can be started right after the at least 10 seconds off time has elapsed -- the calibration is complete.

If the behavior is still present, if there are any error codes, without access to the Porsche OBD2 diagnostics reference you are probably going to have take the car in for a Porsche tech's professional diagnosis. I dare say the components are quite expensive and if you have to replace any one of these you want to be darn sure it needs replacing.

 

Thank you for taking the time to respond to my problem.
I have done all of these procedures multiple times. The problem is still there. I did forget to mention one thing.

The ignition switch was causing a problem about 3 years ago. I replaced it with one I purchased off of eBay. Everything was fine until early winter. I replaced the switch again. I have not noticed any problem I recognize as being part of the ignition switch. Is it possible that there is a link between the ignition switch replacement and the limp mode problem?

 

A bad ignition switch can account for considerable and varied misbehavior from one of these cars. I have no even 2nd hand knowledge this could include causing the engine to enter limp mode.

I had the ignition switch replaced in my Boxster due to a very sporadic no crank symptom. Afterwards the behavior never appeared again.

I recall owners seeking to address a suspected bad ignition switch by just replacing the electrical assembly located at the back end of the switch assembly. Porsche stopped offering the electrical portion separately and under warranty the entire assembly was replaced. I do not know if the key tumbler was replaced (but not before being configured to of course work with the keys) but everything else was replaced. The techs told me in just replacing the electrical portion there were too many bring backs.

At some point I did buy just the electrical part from an Audi parts department but I never used the part. When the time came I just had the tech replace the entire assembly. At some point I sent the unused Audi part to someone as I did not need it.

You are faced with I guess replacing the ignition switch (again) with another eBay sourced electrical part, or the entire assembly sourced from either a dealer parts department or from one of the large Porsche parts resellers like maybe Pelican Parts. I'd be leery of using another eBay sourced part. My preference if I was going this route would be to get the part from the factory via buying it from an authorized dealer parts department and having a tech install it.

It is either throwing an ignition switch at the behavior, or replacing parts of the eGas/throttle body system, or having a tech make a diagnosis. He may be able to tell you the switch plays no role thus the concentration would be on what is wrong with the eGas/throttle body system.

 

Thank you again.

I sincerely appreciate you taking the time to assist me.

BOb

 

Good Evening Bob,
Just curious if you ever resolved your limp mode issue in your Boxster? I am fighting one myself. Thanks for your time