Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Nick2508

Members
  • Posts

    6
  • Joined

  • Last visited

Everything posted by Nick2508

  1. It's 18 months since I had the 'throttle body limp mode' problem and it hasn't happened since. As mentioned, I changed the DME relays and ignition switch shortly afterwards - I don't think there was a problem with the relays, but they were inexpensive and I now have a couple of spares. I think the cause of the problem was the ignition switch - when I changed it I had a look at the old one, it seemed to be slightly worn and there was a bit of play in the mechanism. Inside there are a lot (about 8 if I remember correctly) of contacts and a couple looked slightly pitted and had traces of carbon on them - perhaps the tumblers had come out of alignment? If you have a similar problem, I would try turning the ignition on and off a dozen times in quick succession to see if that fixes it, before bothering to buy a new throttle body, MAF sensor, DME, etc. No guarantees, but worth trying as it won't cost you a penny....!
  2. Good news! It's a mystery what causes it - perhaps the DME gets into an inconsistent state, that the 'ignition cycling' or 'leaving the DME on the bench for a day' sorts out? Disconnecting the battery for 2 days would have cleared the DME fault codes - have you managed to 'lose' the air bag fault light? Perhaps the problem was fixed before you did the adaption (did you try the 'ignition cycling'?) but you needed to clear the fault code (by removing the battery) for it to be saved by the DME. Who knows, but we'll quit while we're ahead....:o)
  3. It was a 'high pitched hum' - which went away when I pressed the throttle pedal (I could then hear the butterfly valve moving). A bit confusing, as presumably the motor in the throttle body only turns when the pedal is pressed? I had the engine cover off at the time - when it was replaced you couldn't hear it (unless you opened the door and listened carefully)...so, not a problem. Once the problem was fixed I could hear the throttle body 'initialize' when I turned the ignition on and waited 1 minute (without touching the pedal) - hadn't heard that before. I'm starting to think that it was the electrical portion of the ignition key switch - agreed, perhaps the internal tumbler/contacts had become misaligned and the 'ignition cycling' moved them back into the correct position. I've only just got back from holiday so haven't had a chance to swap out the relays or switch - I'll open them up after I change them and let you know if I see any possible fault/cause. I also wondered about the alarm box under the seat - but the carpet was bone dry and so I didn't bother to take the seat out and check it further (other than pushing the electrical connectors to make sure they were plugged in ok - they were).
  4. Actually, I've since seen a lot of posts on the web about the electrical portion of the ignition key switch. It's another cheap and easy part to change, so may do that as well after I've fitted new DME and Ignition relays. I'll post an update if I get any further info after changing/inspecting the relays and switch...
  5. Ok - I've managed to fix it! Here is what was NOT the cause of the problem: - Throttle Body - MAF sensor - DME - Wiring loom (I had already changed the throttle body and had checked the wiring between the DME and throttle body connector) Today I did the following: a. Checked that the relays in the rear trunk (DME and Ignition) were seated ok - they seemed to be b. Connected jump leads from another car to the Porsche battery - my battery has completely died a few times over the last year (the car is used fairly infrequently) c. Turned the ignition key to position 2 (dashboard lights on) and then off about a dozen times (fairly quickly) I did a. because I wondered whether the DME was being powered up correctly - there are a lot of posts on the web about poorly manufactured Porsche relays (which have a habit of failing). I'm not convinced this solved the problem (I could hear the relay clicking when the ignition key was turned on), but I'll probably change the relays as they're cheap to buy and it will be useful to have a spare one in the car. I did b. because I wondered whether the battery might be 'on the way out' - I was concerned that the battery voltage might be low and that this could cause the DME a problem. I checked the voltage across the Porsche battery with a multimeter (about 12.2 V) - not significantly low, but the battery in the other car was 12.8V. Again, I'm not convinced this solved the problem - I still couldn't hear the throttle body motor when I turned the ignition key on. I then tried c. and on about the 12th time I left the ignition key in Position 2 (on) - this time I could hear the throttle body motor running! Definitely a good sign, so I turned the key further to start the car...full revs, no limp mode, no poor idle, no flat spots...Christmas had come f'kin early!!! With the engine running I used the Durametric to clear the codes. I then turned the engine off and started it again...all still ok....did this a couple more times to check....problem solved. Later I ran another Durametric test - no dreaded P1502, everything ok. I have no idea why the 'ignition cycling' fixed it - could it be a faulty battery (will fit a new one tomorrow), or relay (will replace it when I get a chance) or ignition key barrel (unlikely) or perhaps the DME was in some 'fault state' and the power on/off corrected it (unlikely as I had previously disconnected it for a day which would have reset the DME)? However, I know that Porsche Guildford wanted to start by fitting a new throttle body (£1500 just for the part - identical to a new Bosch one that I bought online for £370), would probably have then recommended fitting a new MAF sensor (£600 just for the part - identical to new Bosch one at a local motor factors for £200), and might then have recommended fitting a new DME (god knows how much that would have cost from Porsche....). I'm guessing that I didn't need to buy the throttle body (or pay £70 to get the DME tested), but who cares - I'm still on a high from getting the car working again! (Actually, the engine is responding brilliantly, so perhaps a new and clean throttle body did make a difference) I also purchased a Durametric tester - well worth the money as I wouldn't have known it was a P1502 fault otherwise. I hope the above helps someone else....and saves them 2 frustrating weeks trying to work out what it could be! Regards, Nick.
  6. Interested to spot this as I have exactly the same problem on my 2000 2.7 Boxster 986. I've fitted a new throttle body and done the adaption procedure....but still get the same P1502 code. If I clear the code with a Durametric it runs fine, if I disconnect the MAF sensor lead it runs fine, but if I reconnect the MAF and turn the ignition off/on I get the same problem. I've thought about changing the MAF, but others posting on the web with a P1502 have done it and it made no difference, so I'm not convinced - also I get no MAF errors from the Durametric, just the P1502. I thought it might be the DME - sent it away to be tested, but no errors found. I also get no CEL light, just the P1502 from the Durametric? If I disconnect the MAF lead I can hear what sounds like a high pitched motor from the engine bay (different from the sound the throttle body makes as the pedal is pushed) when I turn on the ignition, but I don't get that when the MAF sensor is connected? Could it be failing another initialisation procedure before it even gets to try to initialise the throttle? The Durametric shows that the pedal potentiometer is ok (plus it works fine when the code is cleared). As has been said, the fault is mentioned a fair bit on the web but nobody has listed the fix (other than a few posts which said fitting a new DME fixed it or leaving the DME 'out on the bench for a few days' and then re-fitting it fixed it (not sure why that would repair a faulty DME?) If it happened intermittently after using the car I could accept that one of the chips on the board was failing when it got hot, but because it works fine when you clear the code I'm at a loss as to what it could be. If one of the six lead to the throttle body connector was broken or shorting out, surely it would still not work after you had cleared the P1502 fault? Any ideas?
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.