Volvo Guard II Alarm - Repair or Replace?

Badger vs Bodgers · Dec 12th, 2021, 18:55

Evening all, I've been having a look at the alarm situation on my car and it looks like it has a non-operational Volvo Guard 2 system - there's a glass break sensor and LED on the L/H dash speaker. I also have a 2 button fob with no battery cover.

As I continue to repair/upgrade the car I'd like to resurrect the remote central locking at least, and would prefer to have an alarm/immobiliser of some sort operational. Also I'd like to have 2 fobs if possible.

I'm not sure how the Volvo system has been disabled, and I haven't found much info from my searches (maybe I'm just searching the wrong terms?). Maybe a relay or fuse has been pulled?

So here's the questions - is it worth trying to resurrect the Volvo system - which I've heard can be a bit temperamental - or is it worth looking at some kind of after market alarm? If I do try to repair the Volvo system, where do I even start looking, and what spares are available?

Cheers,
Ben

Steve 940 · Dec 12th, 2021, 19:14

Hi Badger vs Bodgers,

I’m in a slightly different scenario, bought ‘94 940 Wentworth estate almost 3 mths ago, no remote with original keys and non functioning alarm/immobiliser.

Recall it was Volvo Guard as one of the first things I did was to get rid of the awful warning stickers on side windows.

Mine has a triangular box in mid point of offside a pillar, presumably sensors, then at bottom of pillar a small rectangle black plastic thin box, perhaps used to
Be stuck to screen, but just now loose. Have bonnet sensors on slam panel.

Not a major issue but wiring looks to go into main harness, so I just decided to leave it as it is. Would be nice to tidy up if possible getting rid of the interior stuff, but I didn’t just want to cut them off in case it immobilised me😀😀

Cheers
Steve

Forrest · Dec 12th, 2021, 22:30

There are significant differences between the Guard I (Steve’s Wentworth) and the Guard II (Ben’s). There are helpful service manuals for both available online. The common problem with both is that the remotes stop working reliably from a distance.

There’s a good write-up here for resolving that problem on the Guard I system.

https://www.volvoforums.org.uk/showthread.php?t=200312

A related problem with the Guard I is that the NLA grey, single button remote stops working. A good thread here on resurrecting them.

https://www.volvoforums.org.uk/showthread.php?t=253183

I have done these repairs on my Wentworth and its alarm and remote still work really well.

I haven’t got to grips with the repair of the Guard II but I could do with fixing a few problems on one of my other 940s. The components of the Guard II are harder to access and some functions require a special OEM programming box. One failure mode is that the rechargeable batteries in the battery-backed siren (awkwardly located in a metal box under the car) decompose and destroy the circuit board inside. There are also a number of very similar looking remotes out there and the chances are any bought on eBay, minus the paper sticker with their part number, will be the wrong one. The correct part for a UK 940 is 9442981.

TonyS9 · Dec 12th, 2021, 23:06

I Think it depends on your expertise and how much of a challenge you want.

The cheapest and quickest solution is an alarm replacement, the main problem will be identifying the correct signals and connecting them correctly to an aftermarket unit.

I have examples of guard 1 and 2, the guard 1 failed some time ago, gradually reducing the range of the remote. I was able to correct this temporarily by adjusting the varicap in the A pillar module, but it did drift off again and eventually a bad start caused some voltage issues which killed the unit entirely. They were never very good with startup, sometimes needing a reboot by disconnecting the battery. Currently I have just removed it completely, bypassing the starter motor immobiliser.

The guard 2 was also removed as it was for a transplant, except for the fuel ECU RFID key reader module. This cannot be bypassed or replaced without changing the chip in the fuel ECU. It is independent from the alarm,and reads a chip in the key, so the engine will not run without a paired key.

If you have guard 2 and the RFID module is faulty it will be more difficult to repair this, otherwise the basic alarm parts functionality is similar and can be replaced easily.

Steve 940 · Dec 13th, 2021, 08:05

Hi Forrest and Tony S9,

Many thanks for your responses, most interesting, and something that I can put on the list to look further into once i can resolve the more pressing matters the Wentworth has.

Cheers
Steve

940volvoman · Jan 4th, 2022, 18:19

I think its worth repairing the original.

I had this scenario exactly a couple of years back and the team at FRF in Swansea were fantastic. They supplied me with the replacement relays behind the glovebox and new remotes.

It was a much easier solution than identifying the wires and fitting an aftermarket kit, something I had done on another vehicle....

Dec 12th, 2021, 18:55	#1
Badger vs Bodgers Junior Member Last Online: Oct 9th, 2023 20:45 Join Date: May 2021 Location: Bristol	Volvo Guard II Alarm - Repair or Replace? Evening all, I've been having a look at the alarm situation on my car and it looks like it has a non-operational Volvo Guard 2 system - there's a glass break sensor and LED on the L/H dash speaker. I also have a 2 button fob with no battery cover. As I continue to repair/upgrade the car I'd like to resurrect the remote central locking at least, and would prefer to have an alarm/immobiliser of some sort operational. Also I'd like to have 2 fobs if possible. I'm not sure how the Volvo system has been disabled, and I haven't found much info from my searches (maybe I'm just searching the wrong terms?). Maybe a relay or fuse has been pulled? So here's the questions - is it worth trying to resurrect the Volvo system - which I've heard can be a bit temperamental - or is it worth looking at some kind of after market alarm? If I do try to repair the Volvo system, where do I even start looking, and what spares are available? Cheers, Ben __________________ If disfunction is a function then I must be some kind of genius.

Dec 12th, 2021, 19:14	#2
Steve 940 Premier Member Last Online: Today 00:05 Join Date: Sep 2021 Location: Stowmarket	Hi Badger vs Bodgers, I’m in a slightly different scenario, bought ‘94 940 Wentworth estate almost 3 mths ago, no remote with original keys and non functioning alarm/immobiliser. Recall it was Volvo Guard as one of the first things I did was to get rid of the awful warning stickers on side windows. Mine has a triangular box in mid point of offside a pillar, presumably sensors, then at bottom of pillar a small rectangle black plastic thin box, perhaps used to Be stuck to screen, but just now loose. Have bonnet sensors on slam panel. Not a major issue but wiring looks to go into main harness, so I just decided to leave it as it is. Would be nice to tidy up if possible getting rid of the interior stuff, but I didn’t just want to cut them off in case it immobilised me😀😀 Cheers Steve

Dec 12th, 2021, 22:30	#3
Forrest VOC Member Last Online: Today 00:39 Join Date: Feb 2008 Location: Gloucester	There are significant differences between the Guard I (Steve’s Wentworth) and the Guard II (Ben’s). There are helpful service manuals for both available online. The common problem with both is that the remotes stop working reliably from a distance. There’s a good write-up here for resolving that problem on the Guard I system. https://www.volvoforums.org.uk/showthread.php?t=200312 A related problem with the Guard I is that the NLA grey, single button remote stops working. A good thread here on resurrecting them. https://www.volvoforums.org.uk/showthread.php?t=253183 I have done these repairs on my Wentworth and its alarm and remote still work really well. I haven’t got to grips with the repair of the Guard II but I could do with fixing a few problems on one of my other 940s. The components of the Guard II are harder to access and some functions require a special OEM programming box. One failure mode is that the rechargeable batteries in the battery-backed siren (awkwardly located in a metal box under the car) decompose and destroy the circuit board inside. There are also a number of very similar looking remotes out there and the chances are any bought on eBay, minus the paper sticker with their part number, will be the wrong one. The correct part for a UK 940 is 9442981.

Dec 12th, 2021, 23:06	#4
TonyS9 Premier Member Last Online: Apr 9th, 2024 21:44 Join Date: Jul 2009 Location: Holywood	I Think it depends on your expertise and how much of a challenge you want. The cheapest and quickest solution is an alarm replacement, the main problem will be identifying the correct signals and connecting them correctly to an aftermarket unit. I have examples of guard 1 and 2, the guard 1 failed some time ago, gradually reducing the range of the remote. I was able to correct this temporarily by adjusting the varicap in the A pillar module, but it did drift off again and eventually a bad start caused some voltage issues which killed the unit entirely. They were never very good with startup, sometimes needing a reboot by disconnecting the battery. Currently I have just removed it completely, bypassing the starter motor immobiliser. The guard 2 was also removed as it was for a transplant, except for the fuel ECU RFID key reader module. This cannot be bypassed or replaced without changing the chip in the fuel ECU. It is independent from the alarm,and reads a chip in the key, so the engine will not run without a paired key. If you have guard 2 and the RFID module is faulty it will be more difficult to repair this, otherwise the basic alarm parts functionality is similar and can be replaced easily.

Dec 13th, 2021, 08:05	#5
Steve 940 Premier Member Last Online: Today 00:05 Join Date: Sep 2021 Location: Stowmarket	Hi Forrest and Tony S9, Many thanks for your responses, most interesting, and something that I can put on the list to look further into once i can resolve the more pressing matters the Wentworth has. Cheers Steve

Jan 4th, 2022, 18:19	#6
940volvoman Master Member Last Online: Apr 24th, 2024 17:33 Join Date: Mar 2017 Location: Burgess Hill	I think its worth repairing the original. I had this scenario exactly a couple of years back and the team at FRF in Swansea were fantastic. They supplied me with the replacement relays behind the glovebox and new remotes. It was a much easier solution than identifying the wires and fitting an aftermarket kit, something I had done on another vehicle....

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