Fault code P1502

[necad]

Have had an issue for a while on a 2000 boxster. Runs great if you re-set the fault codes using the Durametrics software. Then upon a re-start, no throttle above 1500 rpm's. Replaced the MAF sensor as well as the throttle body. Read that there have been many with the same issues, but no one ever seems to post the whatever the eventual solution was. Has anyone had this experience and was it a reprograming of the dme unit? Was it something else? Searched for broken wires, bad grounds, disconnected everything for a period of time, did the 1 minute on, then off, then start, nothing.

[Loren]

Is that the only fault code?

P1502 Throttle Jacking Unit, Spring Test – Above Limit

Throttle return time too long.

Possible causes:

– Throttle part

Since you replaced the throttle body - did you perform adaption?

Throttle Adaption

1. Switch on the ignition.

2. Wait one minute. Do not press the accelerator.

3. Switch off the ignition for at least 10 seconds.

4. Read out the fault memory.

[necad]

I've done everything including that, wire inspections, cleaning the new tb, looked for vac leaks, etc.... No other codes, just that.

Read about this same issue all over the internet, but no-one ever seems to show what the final fix was. There has to be an answer, or there are a lot of these cars sitting in garages.

Should have never got rid of my 911!

[Loren]

If you replaced the throttle jacking unit did you clear the fault code?

[logray]

Could you have installed a bad "new" throttle body? Perhaps try bolting your old one on, if you still have it, or borrow one if you can?

[necad]

Yes I reset the fault code and everything runs fine until you shut it off and restart the vehicle then it is right back to the issue.

I do have the old TB. Maybe I'll try cleaning it real good and re-installing it. I've tried everything else.

Someone on another site told me the DME should be reflashed to accept the new TB.?. Anyone try that?

[logray]

As long as it is a compatible part I don't think the DME cares. Although I have read about a re-flash fixing gremlins before.

[mikefocke]

Is the new TB the same part# as the old?

[necad]

Is the new TB the same part# as the old?

As soon as the paint in the garage drys I'll get back to the car. Probably will clean and re-install the old, then do the adaptation and see where that goes. I am 5 hrs away from a P car dealer, and would rather repair it myself if possible. I'm actually closer to Quebec, Canada. Only 3 hrs from there.

Weird part about all this is this issue is all over the internet, yet no one ever has posted what the final resolution to this issue was.

Edited February 12, 2012 by necad

[Loren]

Weird part about all this is this issue is all over the internet, yet no one ever has posted what the final resolution to this issue was.

Not true.

Several people here have resolved the problem with a new throttle body and/or throttle position sensor.

[necad]

Well, I have a new throttle body and this vehicle does not have a throttle postion sensor. I beleive that was the intake version beore this setup.

[Loren]

"P1502 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."

Is anything hindering the movement of the springs?

[necad]

Maybe someone could answer this. I may not be 100% accurate.

During the start up process, the DME unit sends a quick test signal to test the spring return. Does the DME check the throttle body itself or does it check the unit under the dash that sends the signal to the TB?

[necad]

Sent the DME unit out for testing. Stay tuned.

I will post whatever the final fix was.

[necad]

Okay, Time for an update.

Sent my DME unit as well as the security(?) box (under the seat) off to Specialized ECU Repair. ECUdoctors.com. Excellent group of people.

They checked my system and told me that they could not get it to replicate the condition on their system. I rec'd everything back yesterday afternoon, reinstalled the boxes, turned on the key, performed the throttle adaptation, and problem gone.

The only thing that I can think of is that there may have been a loose or bad connection on the box under the seat. And looking back, the problem started when my girlfriend was taking it to the store. So maybe when she adjusted the seat up, a connector was just loose enough to cause an issue?

I wish I had a definitive answer, I do not like intermittent problems. But for now my trips to project meetings will be a lot more enjoyable.

Thank you everyone for your input!

[mikefocke]

Ask her if she dropped anything under the seat and had to retrieve it.

[necad]

No, she said it started fine and she did not even realize anything was wrong until she drove away.

3000 miles later, all is still fine. And, there is a small horn noise when I lock the car. Never did that since I've owned it either.

[bar10dah]

That beeping is probably telling you a switch somewhere is open. Try opening and then securely closing your center console lid. That seems to be the usual culprit.