Need full 2001 Buick LeSabre Custom Wiring Diagram - Sources?

[KeithMc]

Help! I'm seeking an entire schematic set for the 2001 LaSabre engine & body
control systems, including all sensors, so I can start tracing voltages, to see if
there's an out of spec voltage somewhere.

Situation: 3800 Engine. Car keeps shutting down. Initially it was only one
transistor in the ignition pack. (Replaced pack, fixed.) But now the car is
just running along and suddenly shutting down. Been stalled out overnight
on the expressway several times in the last couple of weeks.

Just bought my own OBD2 reader. All sorts of errors are popping up,
pointing to many different sensors (odd they'd ALL go bad in a short time).
In order, I've replaced (Ignition transistor pack), air filter, MAP,
TPS (Throttle Position Sensor) & now MAF. Now OBD2 is pointing to the
heated O2 sensor, the catalytic converter, and the transmission. (yikes...)
I'll deal with a slew of transmission errors later. Need engine running first.
I replaced the air filter to rule out air problems.

While stalled out yesterday, OBD2 momentarily gave me a P1689
(communication error on the delivered torque between EDCM and PCM),
causing it to start but immediately die when I put it into gear.
I cleared the codes, but all sensors (including those just replaced) are still
showing issues. However the car did start and I got it back home,
but with so many OBD2 errors (now close to 40), I don't trust it
won't strand me again, without a full electrical go-through.

With this many signals going goofy all at once, I'm now suspecting a general
power supply problem to the control modules and sensors, dirty connector
(or failed board) on the ECM, or some other global error. (I may have replaced
perfectly good sensors...)

That's why I seek the full schematics of ECM, sensors, etc. I need to ring
out the supplies with a voltmeter to help differentiate dying vs just
"not being powered correctly".

{edit} The service guy at the dealer did warn that some 2001 ECMs
have developed cracks in their circuit board - I should try pulling it,
holding it in hand, and slap it while running to see if things change...
... I want to check voltages before I go that far... {/edit}

Questions:
1) Where can I find ECM & Body control schematic set(s)? Does the
Chilton or Haynes manuals include full ECM and body control module
harness wiring diagrams, or do I need to look elsewhere?
Both C & H are out of stock locally, and the parts place workers
don't know if they'll cover this. The local dealer doesn't have 2001
schematics either.

2) Does the 2001 ECM and body control modules have EEPROM
backpacks to move to another copy, or if I do have to replace one
or another will it have to be reflashed at a dealer?

3) Online schematic sources - Is there a truly free online download source
for 2001 LeSabre wiring diagrams? Everyone Google search shows that I've
tried so far says "sure we're free, but give us your valid credit card anyways
just to create an account". (... Yea, right...)

Advice? Where do I get the schematics to start?

Thanks.
- Keith Mc., stranded in SE Michigan

 

[Homer Jay]

What's the history of the car? Flood damage?
I think you replaced the MAF, regardless disconnect it and see if driveabilty improves.

 

[KeithMc]

Hey Jay, thanks for the prompt reply.

What's the history of the car? Flood damage? I think you replaced the MAF, regardless disconnect it and see if driveabilty improves.

History:
Original family owners (ordered from factory),
never flooded. I recently took it over from my father.

Always been in Michigan outdoors, so standard SE MI exposure
issues may apply. Winter finally arrived here recently, which MAY
be aggravating any connector corrosion issues, etc. (Why I need
a schematic - check continuity, trace to verify voltages, etc.)

I recently changed out ignition transistor pack (the transistor driving
the "4&1 coil" failed).

NOTE: GM 3800 ignition transistor packs have an undocumented
maintenance issue --- The heat sink grease between the pack and
the engine mounting (and heat sink) bracket dries out.
Every 5-10 years, you should pull the pack (six coil screws),
clean off any corrosion between the pack and the heat sink-mount,
re-grease both surfaces with fresh heat-sink grease, and
reassemble.
Otherwise, once the grease dries out corrosion creeps in.
This thermally isolates the pack from the heat sink, and it
WILL eventually overheat and fail.
I've had four GM 3800 engine cars. GREAT engine, but ALL
have had this ignition system failure mode.
I recently took over this car from my father, but hadn't yet
gotten around to doing that preventative maintenance when
it fried. (When it happened, I knew EXACTLY what went wrong.)

Not important, but I also recently replaced all wheels & entire
brake system at wheel level (4 rotors & pad sets, 2 front calipers).

BTW... I'd gone through 6 original matching LaSabre
aluminum web-wheels in the last 18 months. All cracked
due to age/fatigue issues (they were only made for three
years, so all copies are now all at least 15 years old).
I don't weld so I finally gave up on them a month ago
and bought an entirely new set of wheels.

Anyone want 6 LaSabre web-wheels, in various conditions?
If so, (and you're in SE MI) contact me directly... (grin)

For completeness - the ABS control module did fail a few
months ago. Up to now it hasn't affected drive operations
(beyond no ABS and a warning light). I FINALLY found a same
build code replacement module recently. However it's not yet
installed (nor flashed). Note - My research says a major failure
mode for the ABS control module is a connector-to-PCB cold
solder joint crack, so the original module MAY yet be repairable.
It's just a pain to pull and replace (jack up & pull left front
wheel, go in through the wheel well, etc... Ick...)

Other known issues yet to fix:
1) Gas tank level sender failure (a known LeSabre defect.
EVERY LeSabre I've EVER known has had this one!)
2) Replace entire exhaust system (including Converter).
3) Look into an intermittent transmission lockup solenoid issue.
I was about to address all of them when these electrical problems
surfaced, making the car unreliable.

MAF - Can't tell if changing MAF yesterday changed anything,
but once in (and error codes cleared) I could drive the 4 miles
to home, where it now sits.

However, the OBD2 error code count continues to increase.
The codes imply a major electrical issue.

Since most are "unexpected high or low" signals from everything.
I'm hoping it's simply a power supply, grounding, fuse, or
connector problem somewhere due to MI weather.

It may however be a major module problem.
Hence, my need for schematics...

Does this help?
- Keith Mc.

 

[2007LucerneCXL]

Here's a link on the forum for a free Chilton manual, scroll down to post #19 for new login and password. It has wiring diagrams which may help on trouble shooting, not sure if it's as detailed as needed but it's a start.
Free Chilton Online Repair Manual

 

[G-234224]

I’m having a similar issue with my 2001 Lesabre