Electrics: 850: remote transceiver compatibility question

[ASt85]

Originally Posted by tony209

Is that definitely the only box you need to change with fobs? I recently tried this on my 05 C70 with known working items but the fobs didn't work. Also, when I put the original box back, the alarm kept going off until I drove the car, after that the alarm stopped going off.

Definitely the correct box - I replaced them in my long sold 850 and my current C70.

The alarm will go off if you don't initially cycle the locks ie lock and then unlock the car door using the key alone, some suggest doing this three times in a few seconds. The process resets the alarm/central locking module. Then lock the doors using the fob, then only use the fob to lock or unlock the door, when locked using the fob the alarm is activated, unlocked using the fob deactivates the alarm.

If you lock using the fob, but unlock using the key the alarm is activated when the door is opened. If this does occur, re-lock using the key whilst the alarm is sounding, deactivate the alarm by using the fob, re-lock using the fob, then unlock using the fob and the alarm should not sound when you open the door. If it does sound, close the door and cycle the door locks using the fob three times and everything will return to normal.

[CNGBiFuel]

The '98 V70 P1 has either the same unit used in the earlier 850s up to mid/late 1998 or the later '98 updated unit which is used in the P2's in post late '98 models the fobs are coded to the car not the transceiver - the C70 (850 based) uses the same unit 1998 to 2005. If you buy a second hand unit, that unit should come with the fob(s) which will be coded to it.

I can say something is not right here. Either we're talking about a different unit or late units are not coded to the car. Certainly not coded to the car my case - because I have the cream coloured late unit 9472461 in my late model 1999 V70, and it is not coded to any car.
As I said, I confirm, I've walked from 1999 P80 car to 1999 P80 car with these units 9472461 and I'm able to swap as I see fit.
Perhaps the exception to the above statement is 1999 V70s, or it gets more complicated with the P2 - either way there are cases where the above is not correct.

[ASt85]

Originally Posted by CNGBiFuel

I can say something is not right here. Either we're talking about a different unit or late units are not coded to the car. Certainly not coded to the car my case - because I have the cream coloured late unit 9472461 in my late model 1999 V70, and it is not coded to any car.
As I said, I confirm, I've walked from 1999 P80 car to 1999 P80 car with these units 9472461 and I'm able to swap as I see fit.
Perhaps the exception to the above statement is 1999 V70s, or it gets more complicated with the P2 - either way there are cases where the above is not correct.

In P2s the receiver located within the rear view mirror module is definitely coded to the car, the fobs are coded to the unit so in effect can only be used by that one vehicle. Neither the fobs nor the module can be recoded to another vehicle NB the door and ignition keys are coded to the car which means that no part of the security system can be used in any other vehicle as none of it can be recoded. A Volvo main dealer with a web connection to Volvo's system is able to code a new unit or any new part of the system but cannot recode any salvaged part of a P2's security system apart from the drivers side mirror/windows master control module/switch.

In the P80 platform the central locking alarm unit is not coded to the vehicle; the fobs are coded to the unit, the unit can be swopped with its fobs to most of the other vehicles in the P80 range. I do not know if the module's colour indicates any difference in the internal electronics, as far as I am aware it is the relevant part number or part number equivalent that dictates the fitment; the only exception are those very late and very, very few P80 to P2 crossover vehicles where the "new type" control module was used complete with the receiver unit in the UEM (mirror) these are coded to the vehicle and cannot be recoded.

A '99 V70 could in theory be fitted with either type module - if the unit is under the dash it should be possible to swop it with its fobs into any other vehicle.

[CNGBiFuel]

I get the idea Volvo fitted what was in the parts-bin most times.

I'm in the middle of making-up a P80 cheapskates multiple fob solution, and so far most hacks seem to work. I'll cover the hacks, and those I've found fail, soon. Sounds like none of what works here would succeed in a P2.

[tony209]

Originally Posted by ASt85

Definitely the correct box - I replaced them in my long sold 850 and my current C70.

I'll give it another go, not sure what I could have done wrong, it should be just plug&play. My son insists that you also need the white box from under the dash but I thought that that just receives the signal and the black box under the dash decodes it.

[tony209]

Originally Posted by ASt85

In P2s the receiver located within the rear view mirror module is definitely coded to the car, the fobs are coded to the unit so in effect can only be used by that one vehicle. Neither the fobs nor the module can be recoded to another vehicle NB the door and ignition keys are coded to the car which means that no part of the security system can be used in any other vehicle as none of it can be recoded. A Volvo main dealer with a web connection to Volvo's system is able to code a new unit or any new part of the system but cannot recode any salvaged part of a P2's security system apart from the drivers side mirror/windows master control module/switch.

In the P80 platform the central locking alarm unit is not coded to the vehicle; the fobs are coded to the unit, the unit can be swopped with its fobs to most of the other vehicles in the P80 range. I do not know if the module's colour indicates any difference in the internal electronics, as far as I am aware it is the relevant part number or part number equivalent that dictates the fitment; the only exception are those very late and very, very few P80 to P2 crossover vehicles where the "new type" control module was used complete with the receiver unit in the UEM (mirror) these are coded to the vehicle and cannot be recoded.

A '99 V70 could in theory be fitted with either type module - if the unit is under the dash it should be possible to swop it with its fobs into any other vehicle.

My brother worked on the P2's security system when he worked at MITEL in Lincoln, he told me about the then new Volvo Estate that was brought in a container and kept in a room with blacked out windows. The PCB and chips had to kept in a safe when not worked on.

[CNGBiFuel]

For cheapo variants, I can tell you one thing, any factory-key has a coil which works with the immobiliser-ring on P80s. I had it you could move the ring, hidden up in the dash somewhere, and cable-tie the key' and its moulded-in coil up there with it. Thus any old £10 lash-up key-cuts could start the car, and be cut ad infinitum. Not so.

The ring is very picky and throws a tantrum. At the very least you've got to put a steel washer or similar up with the IR or the inductance change is enough to throw a P1670 code. The IR likes to sit on a lock-barrell, thus I actauly put a whole spare barrel up in the dash to mine.

Because I've got two 9472461, each with one fob, I'm playing with 2 x FOB ECU 9472461 wired in parrallel to one car at the moment, with reservations, seems to work. I'll write more later.

[ASt85]

Originally Posted by CNGBiFuel

For cheapo variants, I can tell you one thing, any factory-key has a coil which works with the immobiliser-ring on P80s. I had it you could move the ring, hidden up in the dash somewhere, and cable-tie the key' and its moulded-in coil up there with it. Thus any old £10 lash-up key-cut would start the car. Not so.

If you remove the chip from the last original key and tape it next to the ignition switch immobiliser ring under the plastic steering column shroud, it gets round that problem so any cold cut key, copied an original chipped key, will work.

[CNGBiFuel]

I tried that, and my IR is very very picky. The key must be very close and even fails to work consistently unless perpendicular to the bloody lock-ring. Dmaned thing, mine works more like an obstinate teenager.

Anything less and it'll dangle me by starting then to conk 2-3 secs later. I'm at the age where I'm old enough not to care what others think, I wouldn't mind, £1800 on a good day, no one would want my car anyway - the thing's a shed!

[ASt85]

Originally Posted by CNGBiFuel

the thing's a shed!

Could this be a new Discovery channel series................Mine's a "shed" what's yours?