12 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHRough idle, no power, code P1502
Leading reported evidence
Run better, responded
Performed · outcome unconfirmed
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1
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Performed · outcome unconfirmed · Original poster
I started the car again when it had cooled down some and it ran better, responded to the throttle, but the idle was unusually high.
Leading evidence: 'Run better, responded' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check when i get home' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
I need to check when I get home to make sure what I bought was for throttle body and not carb cleaner...
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Suggestion
Note the throttle cleaner is not plastic safe (hence my caution to remove the electrical parts if cleaning the outside of the throttle body).
Clean throttle body's, most parts stores will have it
Suggestion or failed attempt
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Suggestion
There are special products to clean throttle body's, most parts stores will have it.
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Suggestion · Original poster
I will try cleaning the throttle body, clear the code, reset the throttle adaptation and see what happens.
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12 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T212127Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
My '01 C4 cab has a somewhat intermittent problem whereby it will not respond to throttle input and will idle very rough and the RPMs will hunt up and down.
It has happened twice in the last week. Once when we arrived at a destination (car was warm). Upon restarting 1.5 hours later all was well and car was driven two subsequent days with no problems.
Today, this same problem occurred again during a return trip home. I could manage to coax about 1800 RPM in neutral, so I limped home at about 10MPH. I started the car again when it had cooled down some and it ran better, responded to the throttle, but the idle was unusually high.
My code reader says code P1502, which for my DME version equates to "Throttle Jacking Unit, spring test above limit". Searching around the internet has not helped me really understand either the problem nor the solution.
The term "replace throttle part" has come up a few times in my search but I don't know what part is at fault.
Does any of this sound familiar to any of you, and if so what is really going on here?
The DME is not seeing the throttle go to full idle position and because the throttle pedal position does not correspond the the actual throttle position, the DME goes int limp mode. Try cleaning the throttle body inside where the throttle plate meets the throttle body at the idle stop. Do not use carb cleaner, the inside of the throttle body has a special coating and regular carb cleaner will wreck it. There are special products to clean throttle body's, most parts stores will have it.
Preform step 2 and 3. If the code returns you will have to replace the throttle body and preform steps 2 and 3.
I think he is on the right track. Something has happened to your throttle body. He is correct - A good place to start is by cleaning it with Throttle Body cleaner, not carb cleaner. If it were me, I would remove the throttle body, remove all the electrical components and give it a good cleaning with throttle body cleaner. The Porsche P1502 -
http://www.renntech.org/forums/topic...le-code-p1502/
I've heard of this on domestic cars but not on Porsche. However, to be safe, I also use the cleaner designed for throttle body just in case. Would be curious to see if someone has more info.
http://www.crcindustries.com/ei/prod....aspx?id=05081
http://www.crcindustries.com/auto/?s=05078
From what I can tell they are different base types. Note the throttle cleaner is not plastic safe (hence my caution to remove the electrical parts if cleaning the outside of the throttle body). Throttle cleaner is acetone based while the carb cleaner is alcohol based. For my money (and experience), since we have throttle body intakes, use a throttle body cleaner. The appear to be different and why argue the point?
These cleaners are nasty! The data sheets say carb cleaner contains Acetone, Toulene, and Methanol. Throttle body cleaner contains Acetone and Heptane isomers. I'm no chemist but they all sound pretty corrosive.
I stand corrected, I should have used the words "May be coated" better to error on the safe side.
Also Removing the throttle body is the preferred way to clean it, this solves the problem 75% of the time.
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