Whats an Immobilizer??

Every now and then, my 2001 V40 wagon will not start. No cranking, no
solenoid click, no nothing. Try all day, turning the key does nothing.
Wait a day or two, and it starts right up. I also tried it in neutral
thinking the shift switch was flakey. Tried a new starter thinking it had a
dead spot. Also tried the spare key thinking the key's theft smarts were
dead.

So, I broke down and brought it to Volvo.
Two fault codes were on the system
One had to do with the temp sender, the other had to do with the
immobilizer.
I was told either could cause this problem...both will run over 500 bucks
each.

So, I'm stuck with giving one a try...then the other, and hope the tow
charges don't add up too much!!

My question is ...what is an immobilizer, and what the heck does it do...or
not do?
Anyone hear of one going haywire?

Thanks!
....Dave

 

i think the immobilizer is tied into the security
system....

 

Hi Dave,

The immobilizer does what it says: It immobilizes the engine when the
security system is set.
I checked mine ('97 850) by opening the driver's window then locking the
door with the key to set security. (Red LED flashing on the dash.) When I
reached in through the open window and turned the key in the ignition, guess
what......as in your case, "nothing happened".

Good Luck with the fix. (Wish I had my trusty '93 240 wagon back. No
complex immobilizer! Who'd want to steal a 240 wagon?!!)

Andy I. ('58 445 "Duett" wagon; '65 122S wagon; '67 121 direct import
2-door; '74 140 wagon; '74 140 2-door; '86 240 wagon; '93 240 "Classic"
wagon; '97 850 AWD Turbo wagon.) Incidentally, all stick-shift...... our
preference.


: Every now and then, my 2001 V40 wagon will not start. No cranking, no
: solenoid click, no nothing. Try all day, turning the key does nothing.
: Wait a day or two, and it starts right up. I also tried it in neutral
: thinking the shift switch was flakey. Tried a new starter thinking it had
a
: dead spot. Also tried the spare key thinking the key's theft smarts were
: dead.
:
: So, I broke down and brought it to Volvo.
: Two fault codes were on the system
: One had to do with the temp sender, the other had to do with the
: immobilizer.
: I was told either could cause this problem...both will run over 500 bucks
: each.
:
: So, I'm stuck with giving one a try...then the other, and hope the tow
: charges don't add up too much!!
:
: My question is ...what is an immobilizer, and what the heck does it
do...or
: not do?
: Anyone hear of one going haywire?
:
: Thanks!
: ...Dave
:
:

 

If you can, disable the immobilizer by pulling the fuse. Don't know
what else is on that fuse (if any) for your V40.

 

Wouldn't that defeat the purpose of an immobilizer?

 

According to my manual ('00 V40) Immobilizer, Airbag, DSA and
instrument cluster (fuse #11).
But I guess, pulling the fuse will activate the immobilizer
immediatly.


Roland

 

I have not checked, but my guess is that pulling the fuse would default it
the wrong way....won't start. Doesn't that sound correct?
....Dave

 

Try it and let us know. Depending how "smart" those engineers are...
I'm willing to bet that pulling the fuse will kill the immobilizer.

My point was trying to isolate the problem. Since you don't know
which one it is between the two. I'm not sure if you can drive the
car without intrument cluster...

Btw, I pulled the fuse on the ABS for my 240s. (I also disconnected
the 15 yrs old airbag - to each his own).

 

Andy wrote:
(...)

(...)

I've always wondered what that base model 121 was like. Would you
mind describing the trim and interior, and how well the single carb
engine pulled?

 

I would be absolutely stunned if pulling the fuse allowed the car to start.
I've seen some bad engineering, but there's no way something that moronic
would end up in a Volvo. Pulling the fuse will disable the immobilizer, and
the car.

 

Actually, I'm more concerned about the instrument cluster. I have
difficulty imagining being able to start the car without it. The ABS
is a non-issue, and so is the DSA (Dynamic Stability Assistance). So
it only leaves the immobilizer and the instrument cluster.

From a logical point of view, disabling the immobilizer should shut it
down. It all depends how they programmed it in the computer.
Normally, if a protection system is dead, it doesn't perform it's
function.

Again, my suggestion was to try finding which one of the two
possibilities is his problem. Proceeding by elimination is usually
the easiest approach (and often the cheapest).

 

I don't know where you get your logic... The immobilizer is more like the
ignition system or fuel injection system, in fact I would guess it's
integrated pretty tightly into that. Engine management doesn't receive a
signal from the immobilizer system, it won't let the engine start. Like I
said, if it can be defeated by removing the fuse, then it is completely
useless for the design purpose. It would be like a big lock on your front
door held in by just one exposed thumbscrew. If it were the case, every
thief would know about it and there would be publicity very quickly.
Somebody go ahead and try so this stupid thread can end.

Many cars can be started with the instrument panel fuse removed, I wouldn't
advise driving around like that but unless it's on the same fuse as the
engine management stuff, the car will run just the same.

 

Hi "mjc13",

Sorry to say the single carb set-up had already been replaced by a twin-SU
system when I acquired the car so I can't comment on the original
performance.
The trim was the same as our '95 122S wagon. It had front disc brakes but I
seem to remember no servo booster! However it handled well, cornering as if
on rails (or so it appeared at the time......) Exciting too, with a
Kilometre per hour speedo, roaring through the city at 50! (Km/h........)
Fortunately, Canada was just about to change to Metric about that time.
Others were chasing around for stickers to adapt their speedos to Metric.
Of course their odometers continued to register miles

Thanks for your interest.
Andy I.


: Andy wrote:
: (...)
: >
: > Andy I. ('58 445 "Duett" wagon; '65 122S wagon; '67 121 direct import
: > 2-door; '74 140 wagon; '74 140 2-door; '86 240 wagon; '93 240 "Classic"
: > wagon; '97 850 AWD Turbo wagon.) Incidentally, all stick-shift......
our
: > preference.
: >
: (...)
:
: I've always wondered what that base model 121 was like. Would you
: mind describing the trim and interior, and how well the single carb
: engine pulled?

 

I interpreted the immobilizer to be a third party system. Not a
renamed ignition system or renamed fuel injection system.

I remember helping a friend who has a 97 960 and the fuse box
mentionned ignition coil, fuel injection. I guess immobilizer came
later.

 

I'm guessing you mean "'65 122S wagon"! Interesting that the trim
was the same - I had read that they had no bumperettes and much less
chrome. Maybe by that time they had to add that stuff to keep selling
them...

 

: Andy wrote:
:
: > Hi "mjc13",
: >
: > Sorry to say the single carb set-up had already been replaced by a
twin-SU
: > system when I acquired the car so I can't comment on the original
: > performance.
: > The trim was the same as our '95 122S wagon. It had front disc brakes
but I
: > seem to remember no servo booster! However it handled well, cornering
as if
: > on rails (or so it appeared at the time......) Exciting too, with a
: > Kilometre per hour speedo, roaring through the city at 50!
(Km/h........)
: > Fortunately, Canada was just about to change to Metric about that time.
: > Others were chasing around for stickers to adapt their speedos to
Metric.
: > Of course their odometers continued to register miles
: >
: > Thanks for your interest.
: > Andy I.
:
:
: I'm guessing you mean "'65 122S wagon"! Interesting that the trim
: was the same - I had read that they had no bumperettes and much less
: chrome. Maybe by that time they had to add that stuff to keep selling
: them...

Hi "mjc13",

I've just checked a photo I took of the old '67 121. The rear end clearly
shows bumper "over-riders". Is that what you call "bumperettes? The side
view shows the usual chrome.
Thanks for correcting the year of our 122S wagon. It would be nice to find
a '93 model!

Cheers.
Andy I.

 

I have to agree with James, re. the logic of the immobiliser. The
purpose of which is to stop any unauthorised person starting the car, my
poor '87 740 has two third party ones fitted (don't ask; it just ended
up that way), one (a single circuit one) is part of the remote alarm,
which also handles remote central locking (very cool!) - this is
manufactured by serpi star. The other system (a two circuit one, every
wire is black) is just an ex BMW, laser line 'contact fob' immobiliser.
I fitted both of these systems (Yes I know! Just who is going to want to
steal it? LOL), and know full well that disconnecting power to either
system will cause a no crank, and/or no fire situation.
A manufacturer installed and specified to modernish standards system,
such as fords PATS would be very tightly integrated into the cars
electrics, they are also usually very difficult to find in the car,
especially the bits that really matter, and the wiring is usually
coloured and designed to be as obscure as possible.
It would be really dumb if such a system could be disabled by removing a
fuse.

Best wishes, Ken Phillips

 

Yes but it would help narrow down and id the fault, rather than spend
$500 on the wrong "fix" then $500 on the right one.