'93 Buick Park Avenue won't start: security problem?
Phil Bright
The nights have gotten pretty cold up here in Michigan lately, and
my car's battery was dying fast. After work one day, it was hardly
able to turn over the engine. (After it started, the battery voltage
meter went up to where it should be, about 14V, so the alternator
seems to be fine.) When I got home, I parked it in the garage and
left it until the next night. At that time, I hooked up the battery
charger and let it go to work. I figured that if I charged the
battery and then was able to start it easily, then the problem was
definitely the battery rather than the starter. I put the charger on
"High Charge / Start" mode, and then I tried to start the car. It
didn't turn over at all. I let it charge some more, but got the same
result. I replaced the battery with another one that I had, and got
the same result. I tried jumping it with another vehicle, and it
still wouldn't turn over at all. When I decided to push the car out
of the garage, I found that I was unable to shift out of park even
when the key was in the "Run" position. This makes me think that
perhaps my car thinks that I'm trying to steal it.
Here's what it does:
I open my car door, and the security indicator blinks on and off
since I have a car alarm. I get in and close the door, and the light
goes off. I insert my key with its little resistor chip, and try to
start the car. Various indicator lights come on, including the
security indicator which comes on for about 5 seconds or so, then
turns off. I don't remember if it used to do that or not. When I try
to start the car, I don't hear a blessed thing from the engine
compartment. However, after I let the key return to "run" position, I
hear a click a couple seconds later. Also, when I try to start the
car, the current indicator needle on the charger just stays where it
is, so it doesn't look like the starter is even being energized at
all.
I have two keys, and I have tried using them both. They both used
to work, but neither one helps me out now.
Is it possible that letting the battery go dead and changing it
could have caused the computer's security functions to mess up?
Any help would be greatly appreciated. Thanks in advance.
Phil Bright
Nick
mode prior to your battery going dead. Losing battery power reset the
system. If the ability of the VATS module to read the resistance of the key
is lost AFTER the resistance has been correctly read by the module, the
module will disable the operation of the system to allow continued
operation. Since it failed while running, it knows the resistance was valid
and will operate in "failure" mode so long as battery voltage is
maintained - to allow time for prompt service.
A loss of battery voltage will reset the VATS module - and from this point
on, if the module cannot read the resistance when the key is turned, it will
initiate a 4 minute timer to disable the engine. This cycle will repeat so
long as a correct resistance is NOT read.
A common failure with this type of security system is the ignition lock
cylinder assembly. There are two small wires leading from the harness, up
the column, terminating at the wiper contacts inside the cylinder. Repeated
cycling of the cylinder each time the car is started fatigues these two
small wires (approx 24AWG) and one eventually breaks. Of course there are
other possibilities as to the cause of your problem, but I would say this is
"likely," considering the age of the car.
Diagnostics of this part of the VATS system are not difficult to perform if
you correctly identify the 2 wires in this part of the circuit, and take all
of the usual precautions regarding the SIR system.
Replacing the cyclinder is the normal procedure, but keep in mind that your
old ignition keys will not work in the new cylinder since the key cuts will
not be the same. Also, new VATS keys must be matched to the resistance of
the old, since this resistance value has been permanently stored in the
module. The keys can be measured with a DVOM, and conversion charts are
printed in GM service information to convert this resistance to a VATS code
number (1 to 15). Incidentially, GM has a special tool called the
"PASS/VATS Interrogator," which performs these functions easier when the
"Interrogator" is installed in-line into the security system (or simply to
read the key-code directly).
An alternative, (saving you money) to replacing the cylinder assembly is to
install a small resistor close to the value of the key across the two wires.
You will lose the benefits of the VATS system, since won't really be reading
the key-code. But if the car is old and you aren't afraid of the risk . . .
.
I hope this info is helpful, and do please take extreme caution if you
attempt to perform diagnostics/service on this yourself due to the presence
of the SIR (airbags) wiring located in this area. Once you've seen them
going off, you can appreciate the danger. :-)
If you find that your problem lies elsewhere this time, still keep this info
in mind, because this is a high-failure rate problem with this system. I'm
interested to know how this works out, so please leave a follow-up.
Good Luck,
Nick
Phil Bright <pbr...@winfordeng.com> wrote in message
news:50887590.01101...@posting.google.com...
Jacques Labonte
starter checked out, not the security system
Phil Bright a écrit :
Phil Bright
Thanks for the helpful response. Unfortunately, it looks like the
problem is a little deeper than a break in one of the wires. This
evening, I spent a good deal of time upside down with my head beneath
the dash, gazing up at the bottom of the steering column.
(Previously, I had pulled the SIR fuse and disconnected the SIR
electrical connector at the column.) I disconnected the column's big
electrical connector and put my resistance meter leads across two
likely-looking pins. Resistance was infinity (not really, of course,
but it's more than the meter is capable of reading). When I put the
key in the switch, I then got a resistance reading of 4.7k, which is
the resistance of the chip. So, it looks like the little wires are
intact.
Do you happen to know if there is any way to override this security
feature? Evidently, this is preventing the starter from being
energized, but I'm not sure what controls the starter
motor/solenoid/relay. This problem also makes it so that I can't
shift out of park; I'm not sure how it does this.
If you have any pointers, they would be very much appreciated.
Thanks,
Phil Bright
Mark
loose connection at the AUX Battery Post located under the hood, and feeds a
Fuse Block mounted to the left shock tower. A positive wire from the Battery
connects to this Post, and is secured by a Brass or Copper nut. The Nut was
loose and this caused all kinds of strange problems.
"Phil Bright" <pbr...@winfordeng.com> wrote in message
news:50887590.01101...@posting.google.com...
Phil Bright
Thanks for the feedback; I appreciate your response. Unfortunately,
the problem is more than just not being able to start the car. I also
am unable to even shift out of park no matter what position the key is
in. This makes me believe that it's a problem with the security
function.
Jacques Labonte <jlab...@cooptel.qc.ca> wrote in message news:<3BC5F131...@cooptel.qc.ca>...
Robert Hancock
brake to shift out of park. I don't think the security has anything to do
with the shifter interlock..
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hanc...@nospamshaw.ca
Home Page: http://www.roberthancock.com/
"Phil Bright" <pbr...@winfordeng.com> wrote in message
news:50887590.0110...@posting.google.com...
Phil Bright
Thanks for the help; it has been helpful, but it's also been a blow
to my pride. Yes, it turns out that my car does have the brake
interlock feature; I have to push the brake before I can shift. I do
it automatically when I'm actually driving, but it never entered my
mind that I had to do it when the car's not running. That silly
oversight had me totally barking up the wrong tree. I can shift when
I push the brake, so it doesn't seem to be a security problem.
Of course, I still can't start the thing. So, from the information
that I'm running on now, it would appear to problably be a loose
connection somewhere or a problem with the starter solenoid or
possibly the starter itself. Does that make sense?
I appreciate your help.
- Phil Bright
mark
the next thing I would check would be the purple wire at the starter
solenoid,there should be 12V present while cranking the engine you
might as well make sure you have battery power present at the main
cable while you're there too.if there is no power there you'll want to
check your neutral safety switch next,it's located on the left side of
your engine likely where the tranny gear selector is.the purple wire
will lead into one side of it,and there should be a yellow wire from
your starter enable relay going to it also.check for power at the
yellow wire if you find power there while holding the key in the start
position,then the safety switch is your problem.you may even wanna
try moving the shifter into neutral while trying to start the
engine,I've seen this happen before where the "park" contact will have
gone bad in the switch but the engine still starts in neutral.if there
is no power at the yellow wire while cranking the engine,you'll need
to move to the starter enable relay located behind the left side of
the instrument panel.there will be four wires going into it...2 yellow
wires,a blk/yel wire and a ppl/wht wire.check for 12V at both of the
yellow wires first,there should be power at both yellow wires while
the ignition is in the "start" position.if there is no power at
either,then you'll have to check your ignition switch (and fuses).if
you find power at one but not the other check the ppl/wht wire at the
relay for 12v while in start position,if no power is found at this
wire then check for a blown fuse in the instrument panel fuse box,it
should be a 10A fuse in the number 1 location.if you do have power at
the ppl/wht wire and one yellow wire,then you'll need to check the
last wire on the relay the blk/yel wire,this will not be a 12V wire
though,this one will be a ground wire that comes from your VATS
module.if everything is ok with your key and the module itself,then
there should be a ground signal present at this wire.by setting your
ohm meter to a low resistance (200k)to avoid damaging the VATS module
and checking the resistance to ground in this wire while attempting to
start the engine (also a digital testlight would work and be safer for
the module).if there is infinite resistance then you have a problem
with the module or key/ignition lock.
mark
the eng compartment.it should have power while the key is in the on
position.
Nick
PASS-Key II system you have:
All of this information is referenced from the 1993 Buick LeSabre/Park
Avenue ESM.
1.) The operation of the "security" lamp as you describe is normal. The
lamp is provided a ground by the module for 5 seconds after the key is
turned on to indicate the system is working. With this condition you can
verify that the rest of the cranking circuit works by removing the starter
enable relay and jumpering from terminal 1 (Yellow 10AWG from IGN switch) to
terminal 4 (Other Yellow 10AWG to PRNDL switch) in the harness connector.
There are only 4 wires to this relay, which is located to left of column
under the dash. (Other two wires are PPL/WHT 20AWG from Fuse 1, and BLK/YEL
24AWG grounded by VATS module.)
2.) The module has two outputs besides the lamp. One provides a ground
path for the starter enable relay (which in turn completes a circuit to the
starter solenoid), found on module pin A4 BLK/YEL. The other output sends a
signal (I believe it is PWM, not simply switched) to the PCM (Engine Control
Module), module pin A3-DK BLU. If you are thinking of bypassing this system
you would need to duplicate its outputs using another electronic device.
The inputs to the module from the key reader are terminals B8 and B7
(WHT/BLK &PPL/WHT).
3.) ***The security system has no direct link with the shift interlock.
*** The Shift Interlock Solenoid is operated independently and involves a NC
switch at the brake pedal which breaks the circuit to the solenoid. The
solenoid receives power from Fuse 2 which is Hot in Run/Start and the
circuit also passes through the PRNDL (transmission gear range/neutral
safety) switch, which only allows the solenoid to lock the shifter only when
the trans is in park. Verify that you can shift out of park with the key in
the "Off" position.
4.) Once the key is ON the shift interlock solenoid is powered up. The
brake switch is on the positive side of this, and there are no other
components between the switch and the solenoid. You should be able to shift
with the key OFF >>>After opening and closing the door and waiting -
Remember, these cars usually have "retained accessory power" and this
circuit is included <<< C206 (The large conn. at the base of the
column-you had apart already) is the only connector between the switch and
the solenoid. There are no "electronics" in the shift interlock circuit at
all.
If it wasn't for the fact that you cannot unlock the shift lever by
depressing the brake I'd say the PRNDL switch was bad, out of adj, or has
water in the connections, etc. Both the Cranking circuit and the Shift
interlock circuit pass through the PRNDL and those switches do fail. But
since you can't shift by depressing the pedal (keeping the RAP function in
mind), I really don't see where there is a connection.
If there is always power at the interlock solenoid, find out why - this
should not be.
To verify if the starter enable relay is being commanded on by the VATS
module disconnect the BLACK connector at the Transaxle PRNDL switch (under
the hood - black, centered around shift cable linkage) and check for 12
volts at terminal G (10AWG Yellow wire) when the key is in START.
Sorry for the long message. I am not a "regular" here, but I hope that long
messages are not frowned upon. I'd like to know what is going on with this
car too.
-Nick Carr
Phil Bright
It looks like the starter is bad; I ripped the old one outta there,
and I'm going to try to get a new one tomorrow. You guys are real
knowledgeable on this stuff, and I really appreciate your help. I'll
let you know how it all turns out.
- Phil Bright
Phil Bright
I replaced the starter motor today, and now the car is in working
order. It looks like I'm finally done with that one. I apologize for
the wrong diagnosis at the beginning there.
I'm going to be having another question or two as I try to take care
of some more minor problems on this car. If you feel inclined, your
help is always appreciated.
Thanks,
Phil Bright
Nick
going on the wrong train of thought, and I should have realized something
was wrong when you described the brake interlock "problem." Anyway, sorry
if I contributed to wasting some of your time, but it's good to you fixed
it!
Phil Bright <pbr...@winfordeng.com> wrote in message
news:50887590.01101...@posting.google.com...
madaa...@gmail.com
I went to work the other day in the a.m. and when I got into the car to go home that evening... it fires then dies. I can keep it running if I keep it floored or if I pump the accelerator pedal up and down... but dies when I try to feather the throttle at any position.
I have changed the throttle position sensor, the mass air flow sensor and I have removed the exhaust pipe just to make sure there was not excessive back pressure...
hmmm... my wife has been without wheels for three weeks now, I have many hours under the hood and online and I have spent 380 bucks and my Buick is still not running.. 380 bucks because I bought a scanner which won't read the codes so now I suspect the ECU... which has a reset button... but I think I will disconnect the battery first and when I reconnect it tomorrow maybe every thing will reset and ....
