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)

Loads of Fault Codes - 1999 Porsche 996 3.4 - idles a bit poor

Recommended Posts

Hi all

The engine light comes on my 996 every so often, then goes off a few weeks later. I wasn't to concerned as the car drives well.

So I got round to plugging it into the Durametric to look at the fault codes....


I've got loads of codes, P1340, P1531, P0300, P0306, P0304, P0305, P1585, P1319, P1318, P 1316, P1317, P0301, P0303!


The car drives very nicely, loads of power and seems perfect when accelerating and driving. Feels perfect on the open road.


The issue I have is a "tapping" noise on the engine on idle and a slightly eratic idle  - its not much, but its not perfect. It sounds a bit like my 1955 VW Beetle. I was running 5W oil, but also changed it to 10w a month ago, but the tapping noise is exactly the same. Car has done 96,000m.  


So I'm keen to look at the codes and fix as many things as possible!


So today I removed the spark plug/Coil pack covers on both sides to remove a spark plug from each side, the idea was that I could inspect them and the coil packs to see if there old or visually worn out.


The plugs were NGK FGR6KQE 4 tipped plugs, with BERU coil packs all round. The plugs both looked great, normal grey/brown looking colours. The coil packs were dated Jan 2013 and visually looked clean and tidy. **I've owned the car about 18 months**.  I was hoping the plugs may look old and I could just replace those to see if it improves, a fair £40 and Id get to spend some time hopefully improving the 996.  I noticed that one of the middle "tubes" where the spark plug goes into was a bit wet with oil - the other two were dry. I see that its possible to buy new tubes for about £8 with the o-ring seals. The 3 tubes on the other side all looked dry, so just one that's seeping it seems.


I'll work my way through the list of codes, but if anyone has any advice on these codes id love to hear from you! I see one of them was for a fuel vent, so I'm hoping a couple of codes could be cheap fixes.


Many thanks,





Edited by Poze123
Link to comment
Share on other sites

That's a lot of codes!  I would pursue exactly what you are doing - replace spark plugs and check coils.  Maybe replace all coils.  While your at it, clean the MAF and TB. The fuel vent valve code is not uncommon and usually replacing it fixes the problem.  Do what you plan to do, clear all codes and see what comes back.  Might consider replacing the MAF sensor as well.

Link to comment
Share on other sites


thanks guys for the replies, much appreciated.


ok, I'll drive the car this weekend and see which codes come back - I cleared the codes on Sunday night.


You mention cleaning the MAF unit , on the side of the airbox, I had a look online and it recommends cleaning it with proper MAF cleaner fluid, so I'll remove to inspect them if dirty I'll get the cleaner.


Im not sure what the TB is and the fuel vent part? If you see this post , let me know... :)


I'll order 6 plugs and I'll see what the cost of a MAF is. I won't do the coils as I see there £170 for a set and I can't afford that at the moment. I'll remove the MAF first though to inspect it.


but I'd do anything that's a lower cost or that I can do myself as I'm pretty handy in the garage on the mechanical/cleaning side!


many thanks!

Link to comment
Share on other sites

hi all


Good evening!

So I have used the car this weekend and got these lovely codes:













So just a few codes!

The car runs well, there is a light knocking noise around the cam chain area, sounds like the right side of the engine. Only noticeable on tick over/idle.

When I initially start the car, it revs to maybe 1500 rpm, then down to 800-1000 up and down a little, then idles perfectly around 800rpm after maybe 10 seconds of fluctuating.


The engine management light then flashes and stays on. I only use the car at weekends 


So what's best to start on?


Many thanks



Link to comment
Share on other sites

That is still a lot of codes!  The P1531-1340 code is interesting.  You might consider replacing your Crankshaft Position Sensor (CPS).  If the DME is not getting the right signal from the CPS, then it doesn't know where the crankshaft is in relation to the camshafts and timing of the cylinder firings, thus creating a situation where the cylinders misfire in relation to the crank position and the camshafts.  Another guess is one of the Hall sensors, but I think not because of the misfires on both banks.

Link to comment
Share on other sites


Thanks DBJoe.

Is this the part you mention? ::  http://www.design911.co.uk/fu/prod12461/Impluse---Speed-Sensor-Porsche-986---996-98660611202/


And is this "easy" to fit, or is it a major pain to install...

(I'll do some research now )


If you think this is a possibility, i'll spend the £64 and grab one :)


I have also ordered MAF cleaner and also Carb Cleaner to do the TB. I'll clean these two items once the gear arrives this week.



Thank you

Link to comment
Share on other sites

I doubt it's your crankshaft position sensor (the one in your link). Sounds like bank 1 variocam system and cam issues. It will require quite elaborate troubleshooting. Has the engine been worked on before especially the bank 1 cam/head?


Check out these threads:






Edited by Ahsai
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • 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.