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Troubleshooting the Alarm System
 
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Pelican Technical Article:

Troubleshooting the Alarm System

Steve Vernon

Time:

45 minutes45 mins

Tab:

$0

Talent:

*

Tools:

Wires and spade connectors

Applicable Models:

Porsche 944 Turbo (1986-89)

Hot Tip:

Check this early in troubleshooting

Performance Gain:

Working car

Complementary Modification:

Get rid of old stereo wiring

If you are chasing down a no start situation with your 944, one of the first places you may want to apply some attention to is the factory alarm system. These systems did not age well in the vehicles. While it is very difficult to test the alarm control box, it is easy to bypass it and eliminate the alarm as an electrical no start issue.

The alarm control unit or box on the early 944s is located behind the radio. On the newer cars it is behind the kick panel in the passenger footwell. You are going to need some 14-gauge wire and four male spade connectors to make two jumpers. While I do not recommend driving the vehicle with the alarm jumped, if the alarm is the problem, this can get you home in an emergency. If you want to remove the alarm, you should get a proper bracket and permanently remove and jump the alarm. All Porsche 944 and 951s came wired for a factory alarm.

The space you will be working in up behind the glove box is very tight. If you feel you want more room, you can remove the glove box. Please see our article on glove box removal for additional information.

The factory alarm is located in the passenger footwell behind the floorboard and up above the DME (red arrow).
Figure 1

The factory alarm is located in the passenger footwell behind the floorboard and up above the DME (red arrow).

Pull back the carpet and remove the wooden floorboard (red arrow).
Figure 2

Pull back the carpet and remove the wooden floorboard (red arrow).

The factory alarm box is approximately three inches by two inches by one-inch and sits above the DME (red arrow).
Figure 3

The factory alarm box is approximately three inches by two inches by one-inch and sits above the DME (red arrow). Our project car had the alarm system removed or never installed.

This is what a factory alarm control box looks like.
Figure 4

This is what a factory alarm control box looks like.

If you are going to jump the terminals on the alarm box to bypass it and check if that is your electrical problem, you will need to make two jumpers from coated wire and male spade connectors.
Figure 5

If you are going to jump the terminals on the alarm box to bypass it and check if that is your electrical problem, you will need to make two jumpers from coated wire and male spade connectors.

With the plugs attached to the control box, jump Pin 1 to Pin 4 and Pin 7 to Pin 8 on the larger control module connector.
Figure 6

With the plugs attached to the control box, jump Pin 1 to Pin 4 and Pin 7 to Pin 8 on the larger control module connector. If you jump these terminals and the car will still not start, your electrical problem lies somewhere else.

With the glove box removed you can see the two electrical plugs for the control box, the two-pin connector (yellow arrow) and the eight pin connector (red arrow).
Figure 7

With the glove box removed you can see the two electrical plugs for the control box, the two-pin connector (yellow arrow) and the eight pin connector (red arrow).

Here is a proper connector to permanently remove the alarm control box.
Figure 8

Here is a proper connector to permanently remove the alarm control box. You can see how the number 1 and 4 pins (red arrows) and the number 7 and 8 pins (yellow arrows) have been jumped.

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Comments and Suggestions:
JohnnyB Comments: We managed to resolve our non starting issue which was being caused by a factory installed alarm which seems to only become a problem when the battery is low or removed. The alarm then apparently cuts of the fuel pump thus the car doesnt start even after the battery has been fully charged and put back on the car. We found the solution in the owners manual where the alarm needs to be reset by opening and closing the boot luggage compartment 3 times and funny enough this reset the alarm and the car started no problem at all. Hope this helps anyone that had a similar issue
August 26, 2016
  Followup from the Pelican Staff: Thanks for sharing your repair process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
JohnnyB Comments: I have a 1991 944 S2 with same non starting issue that I think relates to alarm due to flashing lights. I have seen on other posts that the later 944 S2 cars actually have a alarm same as the 968 and I would need to jump wires 1 to 3 and then pins 4 to 5 in the fuse box. Do you have any advice on this and is there a specific amp wire one must use for the jumpers
August 17, 2016
  Followup from the Pelican Staff: I don't have the wiring to compare and see what can be jumped if anything. Can you share the info where you saw this along with the wiring? - Nick at Pelican Parts  
winnie Comments: I have a 944 1989 2.7Ltr non turbo and appear to have a intermittent problem with the Alarm ECU? Can the alarm ECU become intermittent? or does it work or not?

When I start the car sometimes ..it sets the alarm off and the engine will not start. If I get out of the car lock it then unlock it this appears to clear what ever the problem is and appears to reset the alarm.......Does anyone have any ideas?

And if I buy another Alarm ECU unit off ebay etc these are obviously second hand can you get new ones or reconditioned ones, as there is no guarantee that after spend £45+ that will work or for how long??

Thanks
June 4, 2016
  Followup from the Pelican Staff: It could be an intermittent tripping of the alarm.

You may be able to find a local rebuilder. As far as used, you are right. Never know what you will get. - Nick at Pelican Parts
 
thevictor Comments: who can I contact to find out how to bypass the alarm permanently? my 86 944 turbo has nothing, no start, nothing at all
April 24, 2016
  Followup from the Pelican Staff: Try a Porsche repair facility. - Nick at Pelican Parts  
Ktg Comments: Awesome this was the reason for my no start, so now I have a question. How can I permanently bypass the alarm?
February 29, 2016
  Followup from the Pelican Staff: I don't know of a way to bypass it. I opened a post in our forums. A Pelican community member may be able to answer your question.
- Nick at Pelican Parts
 

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