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Tried it this morning with no luck. Some of the warning lights flashed dimly, including a couple of warning lights in the clock, but not the immobilizer light. Next step is to follow Andy's interior light/switch fault checklist, with particular attention to the "Ignition Keyway Switch" portion.
It's best that you now try to reset the alarm unit to eliminate; horn & flashing lights;
To reset the alarm condition and stop the horn, momentarily ground pin II/12 or II/2 (yellow connector with shell off).
I'd leave the connector plugged in and momentarily gnd the unprime wire instead (BR/GN). The reason is leaving all the other inputs floating might just cause it to re-alarm. Worth a try if it's easier than getting at the wire, but it might just confuse things further.
The alarm unit is very easy to get to under the passenger seat, not like the immobilizer with its protective Al cover.
The easiest & fastest way to diagnose the problem to the immobilizer/remote is to just fully disconnect the alarm unit and just jumper pins 4 & 6 of the black female connector.
This will stop the lights flashing & the horn, and allow the engine to crank & start, assuming both the remote & immobilizer are OK. The immobilizer light should function under these conditions.
The easiest & fastest way to diagnose the problem to the immobilizer/remote is to just fully disconnect the alarm unit and just jumper pins 4 & 6 of the black female connector.
This will stop the lights flashing & the horn, and allow the engine to crank & start, assuming both the remote & immobilizer are OK. The immobilizer light should function under these conditions.
That’s actually better - it‘ll take the ACU out of the picture.
If you're comfortable unplugging that black ACU connector and jumping pins 4 and 6 (on the plug), it's a reasonable next step - you'll be back to troubleshooting your original problem(FOB not working). If it does turn out that the immo lost its pairing to the FOB, the jumper will enable you to try re-pairing it. With a working FOB you'll be able to clear the alarm and silence the horn. If you're lucky, that may be all you're dealing with. Let us know how it works out.
Last edited by jay@EZimmoblock.com; 09-12-2020 at 01:56 PM.
Not much progress to report, unfortunately. Need to pull the passenger seat out to get to the ACU, and passenger door is too close to garage wall to open far enough for that. While looking under the seat, however, I found what appears to be a power supply and control unit for the after-market car phone a previous owner had installed. Not sure if that is a factor. Also, even with the battery topped off, the alarm is a weak chirp and lights are dim, as if the battery is weak. Maybe some relay is stuck? I don't even know enough to be dangerous, but maybe going back to Square One and trying a different battery might be helpful. (Current battery is a 3YO glass mat that is on a maintainer.) Need a new battery for the boat anyway, so maybe throw that in there temporarily and see what happens. If that doesn't work, explore the possibility of Jay's immoblock unit working sufficiently to at least get the car running. What do y'all think?
EDIT: I'm also working through Andy's checklist. No love so far.
Confused now. What lights are dim? Dashboard? Headlights? Weak chirp? What, the alarm horn? Wasn't it a full-on steady alarm before? A video would be helpful.
It's not the car battery - sounds like the voltage is (or was) up and you had it load tested. Besides, the amount of current you're pulling from it in it's current state is miniscule.
That said, it wouldn't hurt to do a quick sanity check on the power path (battery, cables, connections at the posts and vehicle). Easy - just need a decent load. Can't crank the engine but try turning on the headlights and high beams Look ok? If not, clean the connection points and repeat. When that's ok, try to get back to the first thing you noticed that was wrong. What was the exact sequence of events and what did you observe?
Did you get my PM earlier today? More info in there.
BTW, Is this a new-to-you car or do you have some history with it, and did everything work ok before?
It's the alarm horn that's weak. Interior lights flash, but are dim. Headlights don't light at all. Checked/cleaned battery ground wire to chassis and to battery again. The ground wire was replaced a year ago with a generic part from the auto parts store after the OEM was causing some gremlins and all was good. Maybe try another ground wire?
The last time it ran was 4 months ago. No problems at that point, and car stayed on battery maintainer for the duration. Went to fire it up last weekend, couldn't get the immobilizer to work- Heard the doors lock with the first push of the button, didn't seem to unlock with the second push and no ignition. Re-tried a couple of times with no "clunk" of the door locks. Got out, closed the (locked) door and discovered that I locked myself out. Not thinking, unlocked the door with the key to retrieve spare fob battery (which turned out to be old and no better than the one in the fob) and the alarm went off, and it was loud, and lights were flashing brightly. That's my best recollection of the chain of events. Nothing has changed since then, except now there doesn't seem to be enough electrical power from the car battery to light everything up and the alarm horn continues to be very weak.
The car battery power issue develop slowly after the alarm sounded for awhile, as if the battery was becoming weak. Still reading 12.8V, though. After cleaning the terminals and chassis ground again today, the alarm horn initially sounded very weak, but increased in volume somewhat after 5-10 seconds.
I've had the car for almost 15 years, and it's been mostly trouble-free.
In case it helps, I had a FOB issue last week. Worked once or twice with no problem then nothing. I noticed the light in the FOB was very dim; after cleaning the battery terminals with no luck, I replaced the battery but the light still remained dim with no alarm response. I reopened the FOB, took some hi-res photos to see if there were any visible issues with the PCB. The main thing I noticed was lots of dust and gunk. I grabbed an old toothbrush and some 91% isopropyl alcohol, promptly cleaned it, then let it sit for a while to allow anything alcohol residue to dry/evaporate. Once reassembled, the FOB light was super bright and I was able to arm and disarm the alarm.
Hope this helps. Before... After.
Last edited by Sagres74; 09-13-2020 at 10:44 PM.
Reason: Add photo
I was the poster boy for that last week. Went to local grocer to show off my brand new to me 993. My friend drove and loved the car. Got to Freddy’s, shopped, came back and the car wouldn’t unlock/disarm. FOB is useless. I’m a noob so I figure I’ll just turn key in door and make it work huh? Alarm goes off. FOB Is still worthless. Lots of folks got to do the blessed laugh-their-***-off at the DB in the 993 who can’t figure out how to drive his own car. Alarm finally stops and I climb into car (cabriolet). I try FOB again and it makes an unlock sound so we start the car and haul *** away. I replaced the FOB battery the next day and it seems to
work with no problem. Just a
little gunshy now. What’s funny though is that while the alarm was blaring we pulled out the owners manual and just laughed at the instructions for emergency alarm bypass. Need key code. LOL. Don’t have one. Have tried to get it from local dealer 5 times. They won’t return my call. And even if I did? LOL. Try doing that sequence in a parking lot with horn blaring lights flashing and myself not fit to drive in the first place. Friend drove for
two reasons: test car and I was loaded. Sigh. Learning new stuff every day!
It's the alarm horn that's weak. Interior lights flash, but are dim. Headlights don't light at all. Checked/cleaned battery ground wire to chassis and to battery again. The ground wire was replaced a year ago with a generic part from the auto parts store after the OEM was causing some gremlins and all was good. Maybe try another ground wire?
The last time it ran was 4 months ago. No problems at that point, and car stayed on battery maintainer for the duration. Went to fire it up last weekend, couldn't get the immobilizer to work- Heard the doors lock with the first push of the button, didn't seem to unlock with the second push and no ignition. Re-tried a couple of times with no "clunk" of the door locks. Got out, closed the (locked) door and discovered that I locked myself out. Not thinking, unlocked the door with the key to retrieve spare fob battery (which turned out to be old and no better than the one in the fob) and the alarm went off, and it was loud, and lights were flashing brightly. That's my best recollection of the chain of events. Nothing has changed since then, except now there doesn't seem to be enough electrical power from the car battery to light everything up and the alarm horn continues to be very weak.
The car battery power issue develop slowly after the alarm sounded for awhile, as if the battery was becoming weak. Still reading 12.8V, though. After cleaning the terminals and chassis ground again today, the alarm horn initially sounded very weak, but increased in volume somewhat after 5-10 seconds.
I've had the car for almost 15 years, and it's been mostly trouble-free.
OK. Wasn't clear from your first post that the FOB actually did work (ONCE, when you locked). That means the FOB and immo are still paired, so don't worry about programming the FOB. At this point I'd normally turn my attention back to the FOB (and it wouldn't hurt to follow up on Sagres74's suggestion), but the dimming lights and weaking alarm are a concern, especially since you had the battery "load tested". You might want to do a quick check: With nothing on, read the voltage right on the battery posts. 12.8-ish? Turn as much on as you can and read again. If little or no change, the battery's probably OK. Lights still dim? Gotta be a cable or connection. Not sure how the headlights not working tie in with everything else but you never know. Check fuse 22 and fuse 23.
BTW, what "gremlins" made you change the ground cable? Anything like what's going on now?
Last edited by jay@EZimmoblock.com; 09-14-2020 at 12:47 AM.
OK, before going on to embarrass myself, in my defense, the guy at the shop I took the battery to for a "load test" confirmed three times that he did a load test and the battery was perfectly fine. As you might guess by now, it wasn't. Never had a situation where the battery reads full voltage, even takes a bit of a charge to top it off, but dead as a doornail.
Bought a battery for the boat, but first wedged it into the corner of the frunk, connected it, alarm horn blared, and was able to turn the alarm horn off with the fob. Went to the store for a car battery, slipped it in place, fob did it's thing, and car started, just like the good old days.
Learned a few things here, though-
-Never really knew exactly what a "load test" is, but it basically requires nothing more than turning on some electrical components (lights, etc) and measuring voltage directly on the battery terminals to see if there is a significant drop. Always thought it was more of an exact test involving specific testing equipment.
-Need to get a second fob. Fortunately, it wasn't needed this time, but luck might (and probably will) run out some day. (Best places to buy a fob? eBay? All are the same frequency as ROW? Buy only a new fob? Where do you keep the spare fob?- home or in the car?)
-Learned a lot more about the immobilizer and alarm and diagnosing possible problems. Will finish cleaning switches just as a preventative exercise. After 25 years, there is bound to be some gunk lurking in there.
-Learned the fob circuit board could use a cleaning, too. (never gave that a thought!).
Anyway, I am very grateful for the help, experience and expertise from everyone, particularly Loren, Jay and Andy. Thank you. Is this a great place, or what?
09-10-2020, 04:55 PM
Great to hear, Jim. Congrats. As they say, rough seas make good sailors.