New to 996, question about radio and keyless entry

Hi all, I'm new to the forum and preparing to buy my first Porsche 911. I have my eye on a low mileage 1999 C4 that has the stereo replaced with a Kenwood unit and an amplifier as well. The dealer said that because the factory head unit was replaced, and the keyless entry is somehow tied to that circuit, the keyless entry doesn't work. You can lock/unlock, arm/disarm the alarm with the key in the door. Is there any truth to this statement? Is the a workaround? I'm mechanically inclined and comfortable with wiring. Thank you

Dunno about a 99 C4, but my '01 C2 has a kenwood and the keyless entry works just fine.

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Makes sense to me. I can't imagine that Porsche would engineer a keyless entry module into a radio. So the likely scenario is the receiver is broken, someone unplugged something during the install, or the transmitter needs a new battery. Is this something that would generate a fault code in the ECU?

There is a switch behind the front plate of the console where the head unit sits. That switch interlocks with the rest of the alarm system. It is designed to work with the OEM radios to help prevent their theft. If you replace the head unit you need to disable the switch. I haven't had to do it but I'm sure a search on here will bring up results to DIY the fix. It sounds like someone butchered the circuit somehow rather than disabled the switch. The head unit has nothing to do with the remote entry or the alarm system beyond that switch.

Plenty of people have aftermarket stereos (I have a Pioneer), and keyless remote works fine.

Yes I think the dealer is pulling your leg. I also have a Pioneer radio and my keyless is working just fine. I would have them check all of the fuses and relays before making any major decisions.

When you say "dealer", do you mean "Porsche dealer"? Or, "used car lot" dealer? Clearly a Porsche dealer would understand the security system and how aftermarket electronics work (or don't work) with it. It sounds to me like this particular dealer neither understands or even cares to understand exactly what's going on or why. They simply gave you the "easy answer" in hope that you'll accept it and move on with the sale. Are there two keys/remotes with the car?

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This is exactly what I am thinking. It is possible, even likely, that the dealership has no idea how the alarm/remote circuits work on a 996. They are much more complex than typical for the time period. It is possible the remote is in sleep mode. There are two conditions, that I know of, that cause the remote to go into sleep mode. The first is that you do not unlock the door with the remote for more than (I forget the exact number of hours but it is roughly 5 days) and the second is if it receives more than 256 unsuccessful pairings before receiving another successful pairing (this is one reason the remote range is so much shorter than the average car). The first of these is to save the battery but also to stop listing for transmitters while obviously in storage. The second is like the idea of three tries for your password and if it stills fails you are locked out. It helps avoid the old "code scanner" type theft. The thing is, unlocking the car, even starting it and driving it and relocking it does not turn it back on. Since a faulty remote system is a pretty good bargaining chip (don't even consider the car you will get financially annihilated fixing it) you may want to try this without the dealer around. I believe the sequence for that car should be: -insert the key into the door and turn the key to the left, you should hear the door unlock -with the key still in the cylinder, press the remote entry button, you should see the dashboard LED fast pulse -turn the key back all the way to the right relocking the vehicle -remove the key from the door at this point the system should be out of sleep mode -press the remote entry button to unlock the car and open either the driver's or passenger's door. If the remote worked it is "fixed". The car needs to see all three events to wake up 1. door cylinder successfully turn by key, 2. RFID in key that is paired to the immobizer, 3. the press of a valid type transmitter button while the cylinder is engaged and the RFID pill is recognized. If the remote still does not work either the remote is bad/dead, the immobilizer/alarm is buggered or something has been jury-rigged by less-than-stellar-audio-technicians/owners. Be aware also that the remote range on a 996 is usually around a 6 foot radius from the driver's side A-Pillar instead of the usual 100-150 foot range. The point about two keys/remotes is also far more important than on many cars of its era. Getting a new key for a 996 always involves the dealership and even with buying used parts or online parts and cobbling them together you will end up at a dealership and spending between 200-500 dollars for the privilege. Losing your only key can get very expensive and may require the replacement of the immobilzer module just to be able to drive the car again. A hidden expense best avoided.

Yes, this is a used car dealer, not a Porsche dealer. Although, he represented himself as knowledgeable of Porsches and a 20 year PCA member. I'll research that switch as this sounds like a simple fix. It could also be fuse related since there is an amplifier and it may have been wired incorrectly. Otherwise the car is stock, the miles are low, the price is fair, and the IMS and RMS have been updated. Still worth taking a look.

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Very helpful, thank you.

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Do yourself a favor. Never consider Porsche knowledge and 996 as one and the same. If you buy it find a 996 specialist it will save you tons of money and maybe keep the car on the road. Very few of the air-cooled era Porsche shops are equally good on the 996s. It sounds like a nice car. I will say though that, until they are all gone, I would never buy a 996 that has already had the IMSB replaced unless it was accompanied by a receipt from Flat-6 Innovations themselves for the work.

I have a 99 C4 Cab and two keys. It has an Alpine radio installed. One key works great with the unlocking and locking and setting the alarm and the other one does not work at all with the FOB. They both work fine in the door latch. So unless the radio installer did something not correct or there is something else I don't know, The key less entry should work fine with the aftermarket radio.

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I'm not sure on this but did you try the "wake from sleep" sequence above with the failing Fob? Even though the system is awake, a few references I have read seem to imply that the sequence also "learns" the remote much like pairing a garage door opener remote.

Al, I've personally upgraded my car's stereo and have experienced NO problem with the keyfobs, locks, or security system. LoMax, If you only have one working KeyFob, learn from Hammerthrow and get to the dealer and order another one. You don't want to risk getting stuck somewhere with no options.

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Yep I have changed the batteries, cleaned, it up, done the wake' wake' thing and it work once then stops again. I don't think I am going to spend the money to get another one as it works just fine when inserted in the door so I doubt that I would be stranded. That and I don't carry both keys with me all the time.

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I should clarify just for others. The wake from sleep trick can only work for previous paired keys/pills/remotes. If you install new electronics it needs to be reprogrammed. lomax - I think I saw a thread once somewhere about battery drain issues and some kind of a circuit board repair. I could be mistaken though.

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Not helpful; incorrect. At least on my 02. There is a contact tab in the OE radio mounting sleeve that basically confirms the radio is there through ground. If the radio is removed (absence of grounding, iirc) the remote door locks, alarm, etc all work, but you will get a chirp when you set the alarm, which is the car telling you a circuit is open. I went through this when I replaced my stereo w a Kenwood double din. Everything with the keyless and alarm worked fine, but it would always chirp. Adjusted the contact to engage the metal mounting sleeve and no more chirp. Ymmv

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Incorrect how? Is not a metal contact tab designed to contact the radio to provide a ground signal a switch? Is the tab not designed to contact/interact with the OEM radio? Your response clarifies the circuit greatly but it does not invalidate the previous.

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The previous owner left the original imsb in the glove box.

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Interesting, thanks. Clearly, something is off with the installation, or the key fobs. I definitely want everything to work and don't want to spend extra on something so basic to the car. I am planning to see the car in the next few days for an inspection and will investigate the fob situation. What a helpful forum!

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Sorry, i should have worded that differently. I got hung up on "you need to disable that switch", as i thought you were implying it could cause issues with the remote system. Thats what i get for trying to read/post while boarding a plane....

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If you're comfortable with a soldering iron, you could open it up and do a little touch/reflow on all the solder joints - I've read posts where this has fixed the fob...

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Quite all right. I usually try to give as little information as I think will get my information, or more likely merely my opinion, across without overwhelming the poster. These snippet here snippet there threads can get very hard to follow and I find myself giving too much or too little regularly and just enough all to rarely.

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If I was to guess, I doubt there is anything wrong with the car. More likely the fob is dorked. It could be the owner replaced the electronics but didn't know it has to be programmed (which you can only do if you have the tag that comes with the board) by the dealer. A new remote electronics board for a 996 without the code tag is just a small rather dull looking paperweight. Keys are one of the places were 996 buyers frequently get burned. It's fixable but expensive for what you get, time consuming, and inconvenient. I'm pretty sure the cars come standard with two "regular" keys with remotes and one valet key with no remote (I believe it also has a slightly wider blade so that it can lock/unlock the car and start it but not open the oddments bin or glovebox). When you get a car with one key from this vintage it is common to think about buying a key blank and having it cut and getting a fob from the internet and "teaching" it to your remote, maybe 50 bucks. No mater where you buy the bits (four bits, usually bought as three--cut key blank, RFID pill and remote circuit/case) to make the key, ultimately 996 keys require a trip to a dealer or a very knowledgeable indie/locksmith that has access to Porsche dealership-only testers. Your 50 bucks ends up somewhere in the 200-500 bucks range, a trip to a dealership and fighting with yourself for weeks over having to pay whatever the dealer decides to quote. For many of us a trip to the dealership equates to a half day off to get there and back. Good luck and let us know what happens.

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lomax, since it is your money not mine this is easy for me to say I would not leave things as is. Opening, closing even driving the car is one thing it only requires a cut key blank and a matched RFID pill. Turning off and on the alarm only happens from the remote. If your remote stops working or you lose it you can end up driving a very inconvenient car for awhile. If the alarm was on at the time of loss/breakage, you can use the car just fine but you need to open the car and dash for the ignition before you set off the alarm. Once there is no key/pill/fob combo available and the alarm is set, it seems the only fix is to replace the immobizer module and the requisite dealership visit.

Hi All, I had a chance to see and drive the car today and wanted to provide an update. Long story short, I didn't buy the car. My initial impression upon viewing the car was that it has not been taken care of. The car was dirty, and felt neglected, especially for a 3 owner Carerra 4 with 45,000miles. I drove the car and was impressed (first time driving a Porsche), but not blown away. The dealer and I drove straight to a third party mechanic who works Porsches, and they did a PPI. I've bought and sold many cars over the years, but never did a PPI, and boy am I glad I did. Many small issues with the biggest being: 1. Three different brands of tires on the car (some directional, some not), not good on AWD. 2. Computer could not communicate with the car ECU at all, couldn't pull fault codes. 3. Aftermarket Radio would not turn on. 4. Oil in the coolant and a physical blockage in the reservoir line. 5. Missing cold air intake duct from the trunk lid, so it's just sucking in hot engine air. There is more, but it was clearly not well cared for. Thanks for all the help on this forum, the hunt continues.

Wow, smart move Al... you just avoided a huge money pit. But no worries, be patient and you'll land a deal on a great 996 real soon. Just remember this expression, "The early bird may get the worm, but the second mouse always gets the cheese!"

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Wow... That thing sounds like it's a mess! The "dealer" sounds like a piece of work as well...He clearly had no clue about the car (996's/986's) if there was oil in the coolant reservoir... Disaster averted !!! Congrats

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Biggest bullet dodged!

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But... what about the remote? Seriously this is a good example of why you get a PPI unless you know enough to find these things yourself. All of them could have been found at the dealership before it turned a wheel. Sorry it did not work out but mighty glad you dodged one of the "big bullets".

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They couldnt figure out the remote fault codes because the diagnostic computer couldnt connect to the car's ECU. I know a bit about cars, but not enough specifics on Porsches. Either way, I was able to work remotely for 90min while they did the PPI, so my time wasn't wasted. Onward and upward.

Where is the car? Maybe help someone else from getting burned. I actually may feel bad for the dealer. He now has to say the car has intermix to the next buyer

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http://midwestmotorsdm.com/vehicle/1...4-Coupe/763995

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If he choses to not mention it, then I'll feel sorry for the fool that has to live with all the problems.