P0335 Crank Position Sensor - Wiring issue?

2003 996.2 C2 - 118,000 miles. Lots of new parts within past year - New alternator, Y-cable, Starter, Plugs, Coils, Cats/O2 sensors, vacuum lines. Has been running great. Check engine light came on while driving home, then started cutting out and died. Was able to get it started a couple times but wouldn't idle. Towed home and hooked to Durametric (first found/fixed broken wire pin 7 on odbii port). Fault codes P0335 (Porsche fault code 110 - RPM input circuit), P0341 (Porsche fault code 112 - Phase Sensor 1), P0012 (Porsche fault code 322 - Camshaft position with respect to crankshaft bank 1). Cleared codes. Was able to start it up, idled fine for a bit - shut it off and went to bed. Next day it started right up and idled fine for 30 mins, started to warm up, then died suddenly. After it died, the tach started bouncing around and I heard a bunch of clicking from the engine bay. Durametric showed code P0335 only. Figured Crank Position Sensor was bad, ordered that and 2 Cam Position Sensors (just in case). Also found that whatever caused the tach to bounce around also triggered the overrev range 2 counter to shoot up from 7@1461 hours to 29@3599.h hours! Dammit! (It wasn't really overrevved - car was idling/died). I figured oh well, that sucks. I have photos of the Durametric screens a few different times over the past could years, no biggie I guess. While waiting on new CPS, I checked the wiring at the X59 connector and sprayed with contact cleaner - didn't see anything obvious there or at the CPS wiring connector. So - received new CPS and installed today. Car idled fine until it started to warm up then died. Code P0335 again. Started it up again, idles for a few mins, dies again, then does the clicky thing and the tach bounces all around again. I have a short video, will try to attach it. (Overrev counter shoots up to 37 then 55! Sonofabitch lol) So I'm guessing I have a wiring short somewhere between the CPS and the DME, right? After replacing the CPS with no change I checked the Ohms on pin 1-2 of the old CPS and got .9ohms, so that I'm assuming was probably OK as well. I'm going to try and dig into the wiring harness tomorrow - access looks pretty tight towards the back of the engine (around AOS area). I had replaced the starter around 4 months ago and didn't see anything awry then, and car has been running fine. Any suggestions or pointers? I found a couple of posts with similar symptoms and it appears those turned out to be wiring issues so that's the presumption I'm working with. Any help appreciated! Thanks! -Lenny Vehicle photo album, including recent durametric shots and tach video if interested: https://photos.app.goo.gl/9AYnxubrghEFtqXf9 Vehicle history: VIN: WP0AA29973S621470 Purchased 11/2022 - work reportedly done before purchase 92k-100k miles: Clutch, RMS, IMS (pelican), coilovers, Water pump/expansion tank. 11/22/22 @ 102,000mi: Oil, trans fluid, brake fluid change, air filter 2/1/23 @ 104,000mi f/r tires, rennkit bt adapter, cdr23 solder fix 3/28/23 @ 105,683 replace motor mounts (small oil leak @ pass rear top pcv/aos connection?) 5/6/23 @ 106,300mi: oil change Driven DT40 (oil filter inspection, no metal or plastic) 6/1/23 replace windshield cowl/bottom seal 8/2/23 @ 108,700mi front brakes/rotors (power stop z23 kit rock auto), rotate front tires 8/4/23 @ 108,700mi rear brakes/rotors (pagid discs, brembo pads) 8/4/23 rear tires shot, only 4k mi. Alignment and new rear tires @ 108,700 8/25/23 @ 108,900 plugs/coils, new battery, alternator (997 150amp), y-cable, replaced most vacuum lines on top of engine. (Found resonator flap line broken, fixed) 3/12/24 @ 111,000 replaced front control arms, tie rods, bearings, links, etc. cleaned radiators. alignment and inspection, trans mount insert. 4/23/24 @ 112,250 oil change dt40, 1 can ceratec, air filter. 6/12/24 114,000 replace idler, tensioner pulleys (3). Replace serp belt. 8/1/24 replace hvac recirc vent solenoid/motor 10/26/24 replace catalytic converters, both upstream o2 sensors. (Wasptech 200cel cats with x-pipe, checked stock mufflers.) 12/7/24 117,000 replaced starter (Bosch reman FCP euro) 12/15/24 - clutch pedal helper spring, clutch safety switch replacement. 1/26/25 117,500 oil change dt40, air filter, rotate tires, front brake shims/grease/check 3/12/25 118,250 died on way home, 3 codes, also broken odbii port pin 7

Other related posts I found: https://rennlist.com/forums/996-foru...agnosis-4.html How to check wiring from CPS to DME: https://www.renntech.org/topic/31130...comment-165097 https://rennlist.com/forums/996-foru...o-start-3.html Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 2. Display at 20 �C: 0.8 – 1.0 ohms -- Otherwise -- Replace rpm/crankshaft position sensor. Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 3. Display: infinite ohms -- Otherwise -- Replace rpm/crankshaft position sensor.

Im pretty sure the commonality for the first set of codes is the ground i would make sure its clean and tight. Its on the head, bank 1 above the transmission. U can see it if u look up at the aos Beoynd that u may need to graph or occiliscope the cps signal

Thanks! Yep, I see that ground point and cleaned it up - didn't look bad though. Also checked Ohms for CPS at the engine side of the X59/2 connector (pins 9 and 10) - getting same 0.9 reading (same as directly at CPS). Pin 18 has continuity to ground as well, with low resistance. Wiggled around the wiring harness in that area as best I could with the limited access - will probably pull the throttle body to get better access to the top of the engine to check the rest of the harness. If nothing turns up there I guess I'll start looking at the DME side.

Yea u have to check between the dme and the x51 plug. Mice love to get back in that corner. Make sure u back pin the dme plugs. If u go from the front u will spred the .3mm pins and get more intermintant issues.

Quotes source post: 19956553

Thanks again, will do. I let it idle for a bit after wiggling engine wiring harness around and cleaning up that ground point (also added dielectric grease to X59/2 connector) and it died again within a few mins with the original 3 codes - P0335, P0341, P0012. And another cam sensor one, P0344. Can't tell if the other codes popped up again due to moving the harness around or just coincidence. Gotta be wiring related though.

RE: the shielded cable from the CPS to DME: The ground wire in the cable shouldn't be chassis grounded somewhere along the wire/harness, correct? Here is what I've determined: If I unplug the connector from the CPS and unplug the X59/2 connector, I get continuity from pin 18 of the X59/2 plug (engine side of harness) and chassis ground. Which would mean the shield is shorted to ground somewhere along the engine harness, in between the X59 connector and the CPS. Does that sound like my problem?

Side question: Where is a good place to purchase wiring harness repair supplies? I'll probably replace the CPS shielded wire from the X59/2 connector to the CPS itself, and so would need to purchase wire, the female pins to go in the X59 connector, and hopefully a replacement connector for the CPS end (or I guess i could re-use the original connector and just re-pin that.) Would this suffice for the needed connections or should I look elsewhere? Amazon Amazon

That probably would do. I wish there was a list of what pins where used and where but i have not seen it. Not sure where u can look to verify pin size and type.

CPS wiring harness connector appears to be a Bosch 3 wire compact part number 1928403966. Pretty common apparently. I'm learning! LOL https://www.maxxecu.com/store/engine...-bosch-compact

Weekend update: tore apart the engine wiring harness and inspected all wires, with special attention to CPS wire. No issues found - actually, wiring harness looked pretty good. (When testing for shorts to ground earlier, I was apparently checking the wrong wire at the X59/2 connector - Pin 18 is ground for CPS wiring harness/shielded cable, and i was testing pin 19 because I'm an idiot. Go figure. None of the cables from DME to CPS are shorted to ground, and ohms from CPS pin 1-2 are 0.9 at DME.) Pulled off throttle body, alternator and vacuum reservoir to get better access to harness. Unwrapped/removed all the old tape, checked everything, and re-wrapped with new cloth tape and secured everything. Re-routed CPS cable around AOS to ensure no strain. Also used Deoxit D5 on the X59 connectors and grounds. So, I'm pretty confident that the wiring harness is OK - could be a broken wire inside the insulation though, I suppose. I'll just run a whole new CPS shielded wire straight to the DME if I continue to get CPS codes. Put it all back together. I also replaced both Cam Position Sensors while I was in there, since I did get a cam sensor code a couple times over the past few days while testing. Figured it was because of the loss of signal from crank position sensor, but replaced them both just to be safe. Once done I put it all back together and fired it up - ran fine for ~25 minutes (idle and a couple revs/hold to 4k rpm once warmed up). No codes. Prior to this it was dying once up to temp and throwing P0335 every time. Tomorrow will get it back on the ground, let it warm up, and maybe drive it around a little. I can't imagine it's fixed, since I didn't definitively determine the cause, but we shall see. Couple of questions: Could a failing Cam position sensor somehow cause the crank position sensor code to appear (by itself)? And I guess this still wouldn't explain the bouncing tach when ignition ON engine OFF. Is it OK to spray Deoxit D5 on the DME connectors? Anything else you guys can think of? It really really acts like a wiring problem, and maybe just moving the harness around a bunch cleared it up for now (which means it'll probably return later at an inopportune moment). That's all for today - will follow up when I learn more. Thanks all! Lenny

Update - 3 weeks later. Car seems fixed after 1) disassembling wiring harness and re-assembling it, 2) replacing cam sensors, 3) DeOxit D5 spray everywhere. I've driven it nearly every day for the past 3 weeks with no issues, no codes, etc.. Driven in cold/hot/rainy weather, short trips, longer trips, etc.. I guess it's fixed until it's not again lol. I'm assuming that the shielding on the CPS cable was grounding out somewhere but I never found a short or a worn spot. Or maybe replacing the bank 1 cam sensor did it (but that shouldn't have caused the crank sensor codes I think). Anyway - just wanted to update. I did purchase a new shielded cable and connector for the CPS sensor end and I'll replace that if it acts up again (or if/when I drop the engine I'll probably replace it anyway, just for peace of mind).