No CPS signal at the X59/2 plug, is splicing in new wires an option?

I finished up a motor swap a few weeks back and when I went to fire off the car for the first time it wouldn't run, turns over but will not run. Pulled the codes and it was P0335 for no CPS singal. Long story short it seems the crank posistion sensor signal is not getting to the X59/2 plug (pins 9/10). At the CPS I get .9 ohms resistance, then at the pins on the X59/2 plug I get nothing. I tested on a spare harness and those same pins got me .9 ohms. So I'm 99% sure the issue is in the harness somewhere unseen I have a break. As possible solutions. 1) Splice the current harness in the car 2) Unravel the spare harness I have, and run just the wires for the CPS. 3) Replace the whole harness (can this be done with the motor in the car, seems like it would be easier to drop the motor again). 4) Other? Of course I could be completely wrong and it could be something else, I feel I am capable of working on cars, but at times like this I'm going to 2nd guess myself like crazy because I don't want to do more harm than good.

Ian, I have rebuilt two 1999 Carrera 2s. The first had an engine fire, the second (which I still own) had a dashboard fire. I spliced an entire harness from the dashboard/fusebox to the front of the car. I had a similar issue with my car a few years ago. The diagnostic information that I found pointed to my issue being the reference sensor. I replaced the sensor....still no start. I had a spare relay box with all of the relays. I started swapping relays and that was my issue. I personally would unwind the tape from your spare harness and try bypassing just the wires for the sensor. If you screw up your spare harness, let me know. I also have a spare that I would give you. Good luck. Loren over on Renntech was kind enough to bring the factory diagnostic computer to my house and help me, the first time I fired mine up. You can buy the exact tape on our harness from an electronics specialty store. It is called friction tape. If you find a break and decide to splice, I recommend twist the wires parallel, solder, shrink wrap, and friction tape ( retired bomb tech). Your car looks great. Good luck....you're almost there.

Mfletch, After some deliberation this weekend I think your advice is the best, but I've decided I don't want to unwind my spare harness because it is nearly new and I'd like to keep it intact for a later date where I swap it into the car. So now I'm on the look up for a spare harness that has a good CPS, then I'll swap pins and have a temporary solution to prove to me the "new / used" motor works. Then at some point down the road I'll swap over the entire other harness. So if you want to donate (or I'll happily buy) the CPS portion of the loom that would be great, if not you maybe another rennlister? Ebay will be a last resort, but it has proved helpful in the past. Already have the de-pin tool in an online cart so I can get pins 9 and 10 free form the plug.

How about just running a new shielded cable from the CPS to the X59/2 connector (or just straight to the DME if you want)? No need to unwrap the harness (I just went through this with my CPS cable) unless you want it perfectly back to factory spec. It's a bit of a pita with the engine in the car ( but do-able, especially if you pull the alternator/throttle body/etc.). Would be easy to just run a new cable (either alongside the existing harness, or not), especially if just testing/or temporarily until you drop the motor again down the road.

I don't know what year model you are working on but on 996.1 I have seen several cars do this after engine R&R... Turned out that the CSP and CMP Sensor wiring harshness can be plugged into the incorrect Sensor ... They will physically fit and side by side and the wiring is long to enough to plug them in backwards... They are color coded to keep from plugging them in wrong,, but I have still seen quite a few Techs do this.... It's worth mentioning !!!!

Ian, I am happy to give you my spare harness. I may not be able to put my hands on it until Tuesday. I will photograph it and post a picture for you.

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Thanks in advance, that would be amazing, to get this car running without having to drop the motor back out again would be great.

Ian, I located the harness. I will attach some pictures. I bought it back in 2005, so it has been a long time since I looked at it. It appears to be the portion from the dashboard to the engine compartment. It does not appear to include the engine harness. If the wires you need run off the engine harness, they are not included. If you need the engine harness, I used to buy both parts and complete cars from these guys.... https://specializedgerman.com/ If it is part of the engine harness, I would check continuity on both wires. You could bypass the broken wire with a section of new wire and have your car running in a few minutes. If my harness has what you need, let me know. I can send it to you via USPS. I have to warn you....it weighs about 16 lbs and the box is fairly large. I would ask that you reimburse me for the cost the post office charges, after you receive it. [email removed]

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Mfletch, Unfortunately the harness bits I need are not in there, I'm going to reach out to specialized german, I actually got the replacement engine from them, along with a few other parts over the years, maybe they will cut me a deal on a replacement harness. Thanks for the offer on your harness, I do appreciate it.

Ian, I'm sorry that I didn't have what you need. I hope you find the engine harness have your car running soon.

I guess I should have called Specialized German first, because the engine came from them they are sending me a replacement harness, kudos to them for some good customer service. Once the replacement harness gets here I'll pull out the CPS line and cross my fingers that she starts right up.