Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Carrera 4 Control Alarm Unit Electrical Fire

Recommended Posts

Hi, I need urgent advice please, I have a Porsche Carrera 4 911 996 2001, water has been found underneath seat where control alarmbox is situated labelled M535, Part Number: 996.618.262.01, and it is quite serious as the water created an electrical fire that melted control unit. The wires seem slightly corroded and the car will not start. Dash lights illuminate and I have disconnect Control Box. The door has a clicking noise and will not open.

I understand I need to have control box M535 changed that needs to be coded to new key form but curious as to your thoughts to the following:

1) Cost in replacing with new control unit and wiring loom?

2) How far does the wiring loom run if needs full replacement?

Interested in your suggestions and projected cost in fixing the above.



Share this post

Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

In US dollars the control box a MSRP of $423.38 plus programming time.

All Porsche cars have custom wire harnesses and replacement is several day job and the custom harness is several thousand dollars from the Porsche factory (not to mention 6 weeks or more delivery).

You would likely be better off to splice in new wires or find a salvaged donor car that has the right portion of wiring to splice in. IMHO of course.

Share this post

Link to post
Share on other sites

If there was water there, you'll want to at minimum pull up all the carpets to see the extent of the damage...

Share this post

Link to post
Share on other sites

If there was water there, you'll want to at minimum pull up all the carpets to see the extent of the damage...

And clear all the cowl drains and inspect the drain tubes for damage and that they are properly secured.

Share this post

Link to post
Share on other sites


Did you call your insurance cie....

a year ago i have had a wiring fire with my BMW and finally the insurance scrapted my car....too expensive to fix...it should be the same for you or they will fix it with new wiring cable and new control box....that certainly worth a call because if you want to fix it perfectly it could cost you many many thousand dollars and of corse don't forget to ask for dammage evaluation and the repair at the dealership only...trust it will cost a lot more then you can think....

Good luck


Share this post

Link to post
Share on other sites

Thanks for your excellent responses and we will check and strip back wiring/cowl to see extent of wiring damage to determine if we can utilise existing wires instead replacement of new loom.

Yes we are checking with insurance also.

I have been told that replacement of Control Alarm Box does not necessary fix the solution as the wiring harness must also be coded or talk to the control box. Is that the case?

Edited by Maz007

Share this post

Link to post
Share on other sites

We stripped carpet back and wires are all in tack after 10cms and full wiring loom replacement would probably not be required. Problem we encountered while we were inspecting car is a small electrical burn now coming from Passenger Side Dash.

The Control Alarm Box below has seen better days and curious if you guys believe water caused the issue with small fire to control unit box or if you believe it sounds as though it is coming from the dash component?

We are looking to purchase this from insurance company reason now for very discounted price :notworthy: we are curious as to issue with wiring if it is worth pursuing to repair (obtaining part pay down by insurance from portion of payout) or to leave it as is:



Edited by Maz007

Share this post

Link to post
Share on other sites

That unit has without doubt been water damaged. I'm not sure what could have burnt at the dash area.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By Ravi Matharu
      My 99 996 has started beeping twice when I press the key fob.
      It locks and then immediately unlocks.
      Also when opening the drivers side door, the window goes down when handle is pulled but goes straight back up when the handle is released. So the window obstructs the door closing.
      I have the following Durametric Alarm errors:
      Voltage failure during alarm
      Status: not present
      Frequency counter: 1 10
      Voltage failure at terminal 30
      with alarm system active
      Status: not present
      Frequency counter: 1 46
      Control locking synchronization

      Status: not present
      Frequency counter: 2 49
      K lead

      Status: not present
      Frequency counter: 1 21
      W lead ( DME immobilizer)

      Status: not present
      Frequency counter: 1  
      What's the best way to proceed with fixing this?
    • By loganmarriott
      I have a tough question for any advanced Renntech users who have either stripped a 997 back to minimum wiring for racing, or fixed key issues
      Can anyone help with my alarm issues.
      Im building a 997 Track car- using a salvage chassis and the remaining parts from a rolled and written off cabriolet. Im think the key worked to unlock to car before i pulled it apart, but cant be certain as the engine was already out so there were limit functions to activate then.

      Since moving the dashboard and whole wiring loom into race chassis, I can unlock the doors (yes, its the correct key, ive moved the doors over too), and the dashboard lights up to tell me the current odometer values. However the whole time from when the battery is connected, the alarm siren is going off (currently a clamp muffles that noise to save the neighbors). I can put the key in the barrel, rotate, and then still remove it (the Barrel lock appears to electrically be live, as it releases the key).

      My guess if that the key has lost its coding for the alarm system, but I've tried following these instructions, https://rennlist.com/forums/997-foru...working-2.html,
      with all combinations of button holding, pushing the hazard light switch, foot on brake, and key in/out barrel .... without any success in recoding the key.
      Its worth noting the windows dont go through the usual drop down upon lifting the door latch sequence, im assuming this is due to the alarm running.

      Any suggestions.
      - my options seem to be getting the local agent to reprogram the key
      - are there any other steps i should try to revive the key. I do only have 1 for the wrecked chassis's system

      - a final last though is am i missing some switch that needs bridging from the cabriolet circuits to tell if the roof is down/up

      Logan Marriott

    • By Charles Bradley
      My drivers' side headlight was replaced by the dealership after an accident. It has worked fine for two years since, but recently decided to stop working. I get a "check dipped beam" message on the cluster as a result. The turn signals work, as does a single little light on the outer side of the assembly. The main and high beam do not.
      After taking it out to inspect, I noticed that the electrical harness connector on the back was the problem. When I could force it into the headlights socket, the lights all powered up and worked fine, as did the high beam. So a poor connection is the culprit.
      One of the tabs on the side of the white connector was broken off, so the connector wiggles in its place. I imagine that the force of the headlight being pushed back wiggled it just enough that it wouldnt' seat into the headlight assembly. But getting that white connector into the socket and then back into its place without being able to get my hand in from the rear of the light was not apparent.  I also noted that the insulation on all the wires was terribly frayed and coming off in my hands as I examined it.
      But with a new connector in hand, I don't see how to wiggle the old one out. It slides in from the side on the back of the tray holding the headlight assembly, but is blocked from sliding out all the way.
      How do I rectify this?
    • By Nicky_Noodle
      I have a 2004 Cayenne S. I just got it recently, interior lights have never worked. I checked the fuse and it was blown. It calls for a 20 amp fuse but the blown one in it was a 25 amp. I had the key in the ignition if I remember correctly and put the new 20 amp fuse in and everything came on. Side note, I noticed a weird glitch with the light above the rear passenger side door and the switch on the main map reading light. The interior lights had gone off and I turned the back on and the backlight above to passenger side door was very dim. I slid the switch on the overhead console for the main map light and the rear light came back to full strength. I found that odd. Everything then worked fine. I took the key out. Next time I put the key in, immediately heard the fuse blow. Any ideas on where to start?
    • By Vertical
      When battery is dead the electrical system is down, as is the trunk for accessing battery.  
      I have tried connecting positive to red fuse and negative to door arm.  I ran current using jump starter but could not get latch to open.  Does anyone have any other ideas to open truck, e.g. force lift?  Thanks in advance.
      Is this also true for current year C4S?
      Quote for 1999 911:  <<There should be a release cable under one of the headlights. You need to use something to fish it out. If you do a search at renntech.org you will find it.>>
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.