Schnell Gelb

Mike, if the soldering task is beyond your skill/tools - it should be possible to take the old board and new part to an electronics repair place and get them to carefully desolder and repair.. You'll need to search locally for a hole-in-the-wall type place on the wrong side of the tracks ? Maybe someone knows of a small business that would do this by mail ? The problem would be testing the board. It is easy to R&R so just reinstall and drive it? ECU Doctors would repair/replace and verify all the other functions but would be more expensive.

Mike Murphy

For sure. There are a couple of places that work on audiophile electronics gear around here...

But the car will have to sit at the mechanic shop while I drive back and forth (it's 1 hr away), as my mechanic doesn't recommend I drive the car with the ECU in the current state. So while I could probably save $500, which is a lot of money, it's about 10% of the total cost of the repairs I need to make after driving 4 hours total (using my wife's car). The mechanic also found worn chain guides (top and bottom of the actuator on bank 2), so I authorized them to repair that too. Finally, the convertible top needs a replacement, along with 2 new hydraulic rams, so the total cost for all this work will approach $6k.

My mechanic is willing to send the ECU to ECU doctors, which saves me quite a bit of trouble and time.

Porschetech3

This repair and the diagnosis should be a sticky, I have a feeling as these age more this failure will become more common. The price of a NEW DME for the 99 is now close to $ eight thousand dollars !!! Not that very many will buy a new DME, but the cost of a used one and the labor to diagnose this issue can still add up quickly... Nice work Imo, I remember when you first found this issue, you deserve a good "pat on the back" for coming up with a $10 fix for an issue of this magnitude..

Where is our Mod? Can we get a sticky here?

Imo000

I kept the little bag that the new replacement transistor came in but I don't think I have the invoice anymore. But I'm pretty sure this was the kit and it came from here. https://www.diyautotune.com/product/...river-mod-kit/ I didn't use the resistor from the kit just the transistor and the mica (plastic) insulator that went under it. Essentially I just replaced what was fried in the DME.

The following where on the small pink bag the kit was in:

MK-BIP373
PCBv2.2 & PCBv3 ModKit
(1) 330o 5% Res (330QBK-ND)
(1) BIP373 (1) Mica

racerxm5

So I have both P1530 and P1531 code showing recently on the 1999 C2. Sounds like a potential candidate for repair on both banks. The codes starting showing up at the same time. Wondering if that indicates anything in the diagnosis? My car has about 10,000 miles of track driving on it and it still has good power. The codes start showing up on the track after the engine is warmed up and after the track session the idle is rough. I've had to have the ECU rebuilt before due to misfires caused by deteriorated soldering. Track driving seems to create more vibration than Porsche planned for with their ECU design.

Imo000

Make sure you test the heck out of this to be 100% sure what the problem is.

NachoJohnson

Hi, I have similar symptoms on a 99 with 56k. There's a bit of a chain rattle at start up. Can you advise with the shortest possible steps and the approximate cost?

Mike Murphy

Assuming no need to repace the solenoids or tensioners, and all you need to do are tensioner pads, top and bottom, both sides, I’d bet you are looking at 7-12 hours of labor. The pads, gasket/sealer, new valve cover screws, screws for the scavenging pumps, spark plug tubes (are prone to breaking), and sometimes broken exhaust bolts that need to be drilled out if rusted (mine were not) are all going to cost $100-$200, plus oil service. So it could be $3-$5k (Chicagoland pricing).

However, you might find the opportunity to discover “while your’re in there” work. A tensioner assembly, if failed, is like $1300, but that comes with a new solenoid. You might also have the spark plugs replaced whiles you’re in there. And you might also do a bore scoring check since the mechanic will have access to all holes from the top, and would only have to drop the sump plate from the bottom. And then inspection of the coil packs.

JPSummers

The last warm day we had I got mine hooked up to the durametric. Cam Timing at idle: Bank 1= 0 Bank 2 =0, at 2000 RPM Bank 1=0 Bank 2=9
The car runs fine, no misfire, no hesitation, no rough idle. Only the Code P1531.
My workshop is my driveway so if it's wet or cold, there's no work being done. I have yet to remove the engine cover until warmer/dryer weather arrives.
Wondering if the Solenoid and actuator are fine but it's a wiring issue or Cam Position Sensor Issue. I do know Cam Position Sensors can get covered in metal filings or if not seated properly or hooked up properly can send erroneous signals. A $100 CPS is a lot cheaper and easier to replace than a $500 Solenoid or $1,500 actuator assembly.
The DME is NEW from ECU Doctors. It was reprogrammed and cloned due to an Immobilizer issue over the winter.
Thoughts please.

Mike Murphy

^^ Pretty sure the P1531 is specifically calling that the cam position sensor is working, otherwise you’d get a different code. See post #28.

It’s probably the solenoid. Those solenoids fail way too often in my book.

However, you are correct to properly troubleshoot. Make absolutely certain the wiring is not the problem (the wiring is often NOT the problem. The wiring on this car only seems to fail when an animal chews through it.

If you have an early 5-chain motor (3.4), you probably want to plan on replacing both top and bottom tensioner pads while you’re in there.