987.1 cayman s no crank unless I disconnect battery terminal

Hello all I am having issue with my 2007 cayman s . This all started after replace the old battery which was barely working. I did not connect the leads backwards. No crank when trying to start instrument cluster comes on, lights come on, radio, all electronics work. The following faults Brake malfunction, psm malfunction, depress clutch are shown on the dash.car will not allow me to read any codes unless I remove the cables and start the car bit then it reads clean no codes. I’ve done some digging and have tried the following remedies, removed starter and tested it (passed), test the alternator (passed), bad new battery (12.6v). Tested all the fuses(none blown). I’ve checked the immobilizer no damage that I can see. Car recognizes the key begin used. The clutch switch has been replaced. All relays are good not burnt tested good. I’ve taken the positive cable stud on the distributor out there was rust on it I cleaned it off, the cable end going to the battery had some rust aswell I have clean that to the best of my ability as well. I am going to put the car back together and try and take it to a indie to see if they can find the problem. I just wanted to see if any of you fine folk might have any clue what’s happening. I look forward to your replies.

I remove the cables and start the car bit then it reads clean no codes. Wait, what? I have pondered a while here and I still don't understand what you're saying in this sentence. Do you mean with no battery connected your code reader reads clean? One thing I would try? If you have cables put a jumper on it from a second battery and tell us what happens.

The "malfunction" messages are normal once the battery had been disconnected. But the "depress clutch" dash message sounds like there is a problem with the switch (maybe the adjustment of it) or the wiring. If the clutch depression is not being detected, you'll get that exact symptom (not cranking).

A much better answer ^

Although I don't understand the OP completely, he did state he replaced the clutch switch. However there are 2 switches and so it is possible that the one replaced was for cruise control rather than engine start.

Not only is that correct snake but if it's similar to the "ratcheting plunger" style of the 986 a sub adjustment is sometimes necessary, I remember doing it on my base 986 .

Sorry for the confusion once the battery is disconnected, and then reconnected the car starts and with the motor running I am able to read the codes using odII reader(no codes show up). The clutch switch was replaced with a oem as far as adjustments how do you do that, the screw that holds it in place is tight. With the holiday my indie won’t be available so I am still tinkering with it. Today I check continuity from battery to starter checked the ground wires and everything lined up. Battery was reading 12.3v so I jumped the car and it started. With the car running the battery reads 14.6v. when the car started today the clutch switch was not adjusted, only the battery being jumped, the battery in brand new less than a week old.

The cruise control switch is the black and red plunger type, that was not replaced the one above it a white switch with one mounting screw. When the car does start the starter sound healthy no struggle it fire right up. With disconnect the battery I am resting something that allows the car to be able to start again. Whatever that is would be the problem Trying to figure out what that is is confusing I’ve followed the cables no burn marks or corrosion no loose fittings, there doesn’t seem to be any shorts in the cables. i can not find any bent or broken wire near the clutch or battery or the starter. I am lost

I have replaced the fuse for the “clutch interlock” it was a 7.5 amp still no difference, car will only start after reset disconnecting the battery for a couple of minutes. When disconnecting the battery I am only moving the ground terminal.

If the fault was in the clutch interlock switch, there would be a "depress clutch" error on the display. It is possible that the starter is failing and intermittently starting. It happened to my 987 recently. I was fortunate that it re-started on a return trip with a fuel stop. It did not restart the next day. Initially, I thought it was the battery or clutch interlock switch (I had replaced). I did not get the "depress clutch" error and the battery tested good at the local auto parts store. Replaced with a new Bosch R0808N (OE) starter and it has been fine since. There are a few threads on the forum on the starter issue.

The starter voltage 12.5 which is battery voltage the starter turn over if jumped directly from the starter, so my problem is something between the battery and the starter. By turn over I mean the starter spins but the car does not start.the engine moves as if trying to start but does not. Without jumping the starter only inserting the key only the dash lights and electronics come on No cranking of the engine. ? the positive cable from the battery to the distributor are clean and have continuity, cable from the distributor to the y connect next to the alternator read voltage good. cable from y connect to the starter reads voltage good. On the negative side the cable from the chasis to the battery is good but the secondary cable that enters the firewall i am having a hard time finding where it goes to, does that cable have anything to do with the starter , maybe a ground to it. Any help with diagrams would be much appreciated thank you all and merry Christmas !!

Still could be the starter? See this article.

The connecting to the starter show to carry voltage to the starter none have any notice able corrosion. The starter was tested on bench worked perfectly. I have also jumped the starter with it being ( battery voltage) on the car and it grabbed the fly wheel fine, the car cranked but did not start. The key was in the ignition in the on or start position it still did not start. But the starter did it’s job to turn the engine and the clutch was begin depressed. I don’t think the other parameter to start the car where met but I think that shows the starter is good ?? Things to note All electronics work lights/radio/windows/hvac fan kicks on. Engine is not seized moves freely Starter (passed bench test) (when the car does start it does not crank slowly) Battery ( 1week old been hold voltage above 12.3) Battery tested good with tester Terminals clean to a smooth finish) Battery contacts are clean +positive power cable from battery cleaned no more corrosion( no excessive voltage drop on this cable .2-3) Cable from distributor to Y connect to starter and believe engine electronics.( no excessive voltage drop) Cable from y connect to starter. (No corrosion no excessive voltage drop). (-) negative cable, mounting nut, and terminal cleaned. The smaller secondary cable that goes in the firewall I am still looking for a schematic to figure out where it comes back out to so I can test it. After today I am leaning towards a faulty ignition switch. What do you guys think

Along with the other faults (abs/PSM) I do get the “ depress clutch” warning. I am go on going to try and bridge the the clutch wires to see if that helps. If it doesn’t I am going to rule out the switch(it’s brand new). I am going to bite the bullet on a new starter, going to wait until after the holidays so a actual mechanic can look at it before buying the wrong part. Before this problem started I was able to start the car without depressing the clutch, that drove me to replace the switch.

Sorry to keep highs king my own post. My next step is reinstalling everything then trying to hit the start solenoid to see if it starts. This video by another member shows the steps I have already gone through and I am getting the same results. His car is a 987.2 but I think we might have the same problem . The starter he is using in the video looks different than the one I have. Also attached is a picture of my starter and how it is wired do I have everything correct.

If you still need it, here's 987.1 wiring diagram.

Hello All, I hope you all enjoyed the Christmas holiday, I am still tinkering with the cayman while I await the new starter(hopefully this resolved my issue). I am still having trouble finding where the ground going to the starter connects to either the chasis or engine ?. Does anyone have a idea of where it might be ?

@Wilson.cs07 ... Check your private message for wiring harness.

This was found upon inspection. Today it goes to the alternator !!

One thing to do if your still looking for suggestions is to have the battery tested to see if it is putting out enough amps. I had a battery with an internal short that mimicked some of the problems you are listing but still showed good voltage.

Does any happen to know what this connector goes to, it is routed under the passenger side intake. I’m thinking it goes into part 2.

Starter was replaced. Sadly it was not the fix to my problem. It sucks to not have my car but hopefully this next week I can have it towed to my indie( Porsche performance in San Diego). Thanks all for replying I will up date this post with what the indie say is the problem. With these cars getting to a significant age point and some what attainable more people will get cars and have problems. Happy new year to all enjoy your P-cars!!!

It is unfortunate that you've not been able to resolve your problem. Wishing you better luck with the indie and a better new year!

I had very similar symptoms after I flashed the car ( 987.1 ) with a Vivid tune — car started fine after a battery disconnect but then it wouldn’t crank and would show the “depress clutch” and the same lights as you. I replaced the battery and clutch switch but no joy. I finally took it to my indy shop, who diagnosed a bad DME . They sent it out to a place to get it rebuilt, and that solved the problem. I’m going off of memory here, so if it would be helpful, I can dig up the receipt from the job to see if there are any other useful details.

That info would be greatly appreciated if you can find it. I will be talk to my Indy here soon. Any info to help the diagnosis is a +.was it the dme relay or was it the dme / ecu circuit that was found faulty.

Update: Sadly still no fix after hours of troubleshoot, my Indy and I have come to the conclusions that it is ecu / dme related. I am going to be reaching out to ecu doctors to see about getting the system tested. Hopefully it is not too much of a repair after this. happy new year to all !!

sorry to hear about your issues... Do you have access to a specialist who may have other porsches and can assist better with some of this type of troubleshooting? hope you get it resolved soon....

Yes after getting some time I was able to drop the car off at a specialist. the first diagnoses was showing multiple dme connection failures. Me traced it back to what we thought was a faulty ground/wiring in the driver door (other fault codes led us here). we checked all wires and found the fault in the door a couple cracked wires. After reevaluating we found this not to be the cause of main issue. the second diagnoses was a faulty dme even though no fault code showed up in the dme it self. before sending the dme , immobilized and ignition off we decided to load up a updated oem tune file directly from Porsche. When trying to do this the first time the car had the same issue but the codes showed the oem flash did not write over all aftermarket software. So we flashed it again with the same results. The fact that it was not allowing the oem flash to fully write over the current software led us to believe this was the problem. As a last ditch effort we tired one more time, the third time the oem flash went perfect. After flashing the car and checking all communication to the dme it was all good. Car has been starting perfectly for almost a week. I will do a more through write up once I have the time to sit down and look over all the codes and paperwork.

glad the source has now been found - hopefully your story can help others who might come across the same situation.