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At the end of the day, it is your car and your money. Just be aware that there always has been a limit as to how cold an automotive AC can be allowed to get; some manufacturers actually set a minimum permissible temperature for their system in order to prevent some rather strange problems. We actually had a customer that complained his system seemed to be cooling fine and then would just shut off for no apparent reason during a rather warm and humid period. After some intense diagnostics, we discovered that his system was getting so cold (very low 30F air temps), that under some humidity conditions, the car was actually freezing over the inside heat exchanger, blocking air low until it defrosted, giving the appearance that the AC had quit. We traced the problem to an AC compressor replacement prior to his purchase of the vehicle, where the wrong part number compressor was installed that had a higher capacity rating than the factory unit. We evacuated the system, replace the compressor with the correct part number, recharged the system and found the air temps inside the car's ductwork now stayed at around 41F, one degree above the manufacture's minimum allowable internal air temp. The car never froze up again. While getting you system's AC temps as low as possible seems like a worth goal, sometimes the law of unintended consequences rears its ugly head............

I do not have a useful recommendation but would suggest contacting your local chapter of the Porsche Club of America as they typically have background on known Tiptronic repair facilities in your geographic location.

Hi, Thanks for the input. Looks like you may be from PA, do you have any transmission shops you would recommend? The Regulator looks easy enough to swap out, but my guess is a run of the mill shop would just recommend swapping out the whole valve body. I want someone whom I can have an honest conversation with. If they’re going to be in the transmission, they might as well swap out the #4 Pressure regulator and the torque converter plus check all wiring connections in the valve body. The kit on FCP Euro includes all of the solenoids/regulators so I would probably just have them swap everything out (or do it myself). My guess is a transmission shop would be able to diagnose all of the problems you mentioned and discern if it’s the regulator or the torque converter. That said, there are no drivability issues right now, and the car is not a trailer queen so I’d be inclined to drive a reasonable distance to a specialty transmission shop. Any suggestions?

Try 2642

Hi thanks for your response. While I appreciate your opinion regards these kind of products and the systems they are put into in terms of whether you feel they need them or not, with respect that wasn't my question... I've researched these products in depth and know that they do work and have decided that I would like to use them. My question was around if anyone else had used them and how they had gone about that in terms of ratios of product to oil. Once again thank you for your response.

Welcome to RennTech Tiptronic problems are never fun, and often complex and difficult to diagnose and repair, which is why many shops shy away from working on Tips. Potential issues causing P0740: -ATF supply (as you have fresh fluid and assuming it has been topped up correctly, this would only apply if the filter were the problem and not moving sufficient fluid) -The torque converter itself is bad. To properly diagnose this, you would need some very specialized and very expensive tooling. -Pressure regulator 4 is problematic -The electrical triggering connection to pressure regulator 4 is bad (shorted, disconnected) -Hydraulic control unit (read valve body has sticking valves)

I always remain circumspect of "magic bullet" additives, especially those touted on the internet, and particularly when used in very expensive and sensitive systems like air conditioning. The ac systems in these cars have proven to be both effective and long lived as designed, I don't really see any advantageous reason to do this as a well maintained and functioning system doesn't need any help.

Hi, New to the forum, but not new to classic cars, DIY mechanic projects, etc. I’ll give a brief history of the car I bought which is throwing a P0740 code. I have read all of the previous discussions on this topic both here and on Rennlist, but I still don’t see a good diagnostic path or solution. Below occurred prior to my ownership and all work done by a Porsche specialist with 30+ years experience: 1. Oct 2021 - 76,386 miles - new long block installed with L&N IMS bearing. All useable parts from old motor were re-used on new motor 2. Sep 2022 - 79,197 miles - used DME installed 3. Aug 2024 - 81,649 miles - used transmission installed. Used trans was pulled from another car with 52k miles. 9 liters of Pentosin ATF, new gasket/filter/seal/bolt installed I purchased car in Jan 2026 with 83,013 miles and drove it home 400 miles. Car now has 83,8xx miles. Feb 2026 - drove to DMV and while at DMV, had to shut off car so employee could connect scanner. The car would not turn back on and it was pushed out of the bay. I had car towed home, and after reading multiple posts, I diagnosed the issue as a faulty starter relay which was replaced. I then hooked my cheap OBD II scanner up to the car to check for any other faults and noticed a P0740 code. I reset the code, drove to DMV, passed inspection and drove home. The code returned. I took the car to a local Porsche specialist who topped off the trans with a “small amount” of fluid. This was done for free because they owed me a favor. Now the car is home, and I would like to solve the P0740 issue. I have read all of the tech posts and noticed a few paths including low/dirty trans fluid, Pressure Regulator # 4 and/or Torque Convertor. Also noted, no CEL, a hard up-shift at times between 3rd-4th when trans is cold and local Porsche specialist “won’t touch Tiptronics.” So I’m on my own for now, and I live in Delaware. If you have hung in this long, I appreciate you. Seeing as though the trans fluid/filter was replaced 2,500 miles ago, and just topped off within the past few days, I ruled out low/dirty trans fluid. Remember, the used trans installed in this vehicle currently has 55k miles on in. My question is, how do I diagnose if the issue is with the torque converter (which was not replaced when the new motor was dropped in) or, if the issue is Pressure Regulator #4? Please only post constructive comments. Yes, I can drive a manual trans, but bought an auto trans so the spouse could drive the car as well. Long story behind that lol. Thanks so much for your time and comments!

Hello everyone, Could someone please let me know if they have the radio code for my 2002 969 911? CCR 220 BE 6624 S.N.# 15000748 Kind regards, Douglas

Hi has anybody used this stuff in their car? It gets very good reviews online and YouTube videos.. Thing is.. I'm in the UK and over here when you take your car to the garage to get the aircon recharged, they use a premix system that puts in the refrigerant and the pag oil to the correct quantity. It's a big machine that they plug onto your AC system and you can't intervene to add anything. So I'd like to look at using this Cool Ox.. but the internet is saying for a 987.1, the correct amount of oil should be 195 ml. So currently my car is charged up with the refrigerant and presumably the right amount of oil. I've purchased an oil/dye injector that you can connect to the low pressure valve.. but I read that it's not a good idea to put too much oil in your AC system. So let me see if I can explain what I'm asking here... What would be the way to go about this.. would You just put the additive in as well as the 195ml of PAG (.. meaning the Cool Ox would not actually count towards the amount of oil already in there, presumably because it will go to work and be used up coating the metal surfaces), or do you add it INSTEAD of the PAG oil, or would you makeup the 195 ml from both the PAG oil AND Cool Ox..? I hope I've explained that ok... Thanks very much in advance.

Solution found ! Went over to SMS in Huntington Beach. Branden took a light switch out of another Boxster and tested it in my car. Sure enough, it was the switch. Also learned how easy the light switch comes out. Ive ordered a replacement from Pelican. Free shipping…. Link to https://www.pelicanparts.com/techarticles/Boxster_Tech/87-ELEC-Headlamp_Switch/87-ELEC-Headlamp_Switch.htm

Thx! My case is that my car is not MOST, it was analog Bose (MY02 Turbo). So, I was considering using the MOST box to supply any of the available options in the market: Trioma (russian, cheapest), Audison (apparently made by Mobridge) and Mobridge itself. All are expensive but I've spent a lot of money in HiFi, cars, booze and XXXX (redacted) so it would be just a bit more of that 😁 Will check the cable for continuity as well.

Maybe this doesn't quite answer your question because a) it's dark outside now, and b) I don't fancy the grief of pulling my HU out to check - but: My CDC-4 lights up when powered but not connected, My Bose amplifier lights up when powered but not connected, my Mr12Volt bluetooth / USB / SD / Line in interface lights up when powered but not connected, and; My PCM2 used to light up when powered but not connected. I would deduce from this (and the light read through the MOST technical specification 🤓) is that the MOST box supplied with the PCCM+ must light up, otherwise it isn't transmitting on the network and will in fact cause the entire network to fail (all signals pass through, and are replicated by, every device on the loop). Check the connection from the HU to the MOST unit is actually connected and seated properly (without sounding too patronising). If that isn't it then there is a setting in one of the hidden menus to turn MOST off, this might cut power to the box, check this isnt switched off too. You'll need to (very) long press "Version Info" to get the menu up. Failing that, give the vendor a nudge and see if they can spot you a replacement MOST unit. I think they have their own part number so I would suspect Porsche can provide the unit by itself. I do get some information in the MOST row of that screen though. I'd have remembered if it was blank. I can't necessarily speak for sound quality over TOSLINK, I just left mine with MOST as it was easy from an integration perspective. Fundamentally it should be fine as it's capable of linear PCM signal and the iphone over USB connection is also I think PCM and generally regarded as pretty much lossless. You do however have an electrical to optical conversion at the HU, then optical-electrical-signal conversion-electrical-optical in your MOST/TOSLINK convertor, then a conversion back from optical to electrical - how good this circuitry is on the HU, MOST to TOSLINK converter, or your amp when it comes to packet loss and jitter could be a bit of an unknown. The only brand name MOST to TOSLINK I could find when I went through the same thought process was an Audison one which was big dollar (how much of that is just Hi-Fi tax, I dont know).

The two red wires are taps for my back up camera and dash cam….

On my ‘06 987, the fog lights switch will not turn on the fog lights, nor do the little lights by the switch I tested the Fuses 5 and 7 on the top row, they are good. Somewhere, I read that a faulty headlight leveling sensor could do this ?? What is this ? Lastly, will the PWIS detect the problem ?

To anyone who installed a PCCM+ in a MOST 996/986, when you initially attached the MOST box, could you see red light inside the socket when the radio powered up? I have no red light shinning at all. And, for anyone who has currently such a setup, can you check whether the MOST version number shows up in the version info screen? For comparison, I'm attaching a photo of my version info screen, MOST version empty. It appears the PCCM+ does not detect the MOST box. I read about a lot of cases where the MOST box was DOA, I'm wondering if I have another such case. My car is non-MOST and am not going to use it initially at leat but given I have an aftermarket amp with a Toslink input (and only speaker-level inputs, no line-level) I was thinking about getting a MOST to Toslink converter and ensure a fully digital path to the amp. The way it will be now, the PCCM+ converts the iPhone digital stream to analog, amplifies it to speaker level and then it goes down the line to the amp, where it will be digitised again, processed by the DSP stage, converted back to analog and amplified again and finally sent to the speakers. So, I was definitely considering using a fully digital path but that requires a working MOST output. So, can someone please check their "Version Info" screen and see if their MOST shows a version or is also empty, despite working fine?

my ABS pump was not sending fluid to one whee,l I verified the pump the aluminum casing had one of the holes clogged or something I was not getting a drop of fluid out of one hole. I went ahead and ordered a used part from Ebay now my question is. Should I remove the manifold from the old pump and put in the new manifold and use the original electronics from the car or can I just put in the whole new pump? If I just put in the new (to Me) complete pump do I have to reprogram it or something? I know I have to bleed it but do I have to do anything else? I saw one guy on YouTube say that he is using the original computer so he does not need to program anything, is this true?

Thank You !!

It looks like an air bag sensor but the air bag sensor doesn't fit either.

Try 5048

I hope this is the right way to do this. I need a radio code for a 2002 boxster CDR 220 Serial # 15004215 Thanks

not sure if its taboo to post other forums here but i found this super useful and was hard to find: The Definitive 986/996 Clutch / Power Steering Coupler - Union - Connector Thread - Rennlist - Porsche Discussion Forums RENNLIST.COM Boxster & Boxster S (986) Forum - The Definitive 986/996 Clutch / Power Steering Coupler - Union - Connector Thread - After fighting issues with connector leaks at the clutch and power steering unions over the past year I have learned a lot. Much is NOT known (or not...

Hey all, should these just slide on to the hardline? I'm having trouble understanding how these fit and hold on to the hardline. Some threads show that there is a black retaining clip - does that come with these part numbers?

Hey Mark I have the same issue with a no crank/no start with the same codes. My CAN Comfort off was a corroded split point under the passenger seat on the B pillar. That fixed my CAN comfort OFF code. I still had my 1826: Steering Angle Sensor Terminal 30 Power Supply which had perfectly power and ground including the 15 (which is ignition on). I also have no codes in the Kessy and all authorization that I can see with the scan tool. My guessings are the steering angle sensor is the issue or the kessy is the issue. I have to say my friend has the same cayenne and I replicated the code 1826: Steering Angle Sensor Terminal 30 Power Supply. And his cayenne is still starting. So the only thing that still is not working is the Kessy. Did you find a solution what it was? I hope Kessy because I am ordering one