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My 2000 deville has had some weird issues in the past year, but for the past two weeks it has been running really rough when it is first started and yesterday after about 5 minutes of driving the DIC said the car was overheating but there was no actual sign of it overheating (no steam, no water, no hard hoses, etc.). In the past year it has been telling me to fill my coolant and washer fluid and they are full. My gas gauge is fiction, my rear heater doesn't work, the light under the hood didn't work until the car says it overheated. Not sure if is related or not, but I went to the car wash and 15 minutes later is when the car said it was overheating. The gave me codes P1536 (ac issue) B1004 ( KAM) C0663 ( ride level issue). Nothing that has to do with my current issues. My Scan tool says no link and turns on the security and traction control lights. I am thinking maybe the bcm? Any thoughts on this?
 

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1993 Cadillac deville sedan 1986 cadillac deville RIP
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Re: 2000 deville with weird issues

So I ran the codes again and came up with U1016 that says (DTC U1016 Loss of Class 2 Communication with VCM /DTC U1016 Loss of Communications with PCM). Anybody know what color the wires to the PCM are? I believe the PCM is under the air filter. Thinking I should make sure that is grounded good.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Re: 2000 deville with weird issues

That PCM has 160 wires - two 80-pin connectors with retainer bolt. Get a subscription for that car to www.alldatadiy.com . The pinout and pages upon pages of wiring diagrams are in there - it's the GM service manual plus a LOT more.

The wiring harnesses contain the grounds - there is no separate PCM case ground.
 

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2000 DTS
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Re: 2000 deville with weird issues

To check the grounds on the PCM of a 2000 Deville:
Remove the air box top.
Remove the filter and filter housing.
Now you see the PCM.
Remove the two screws holding the connectors in place.
Snip two tie wraps and remove the gray plastic covers over the wires.
Now you can read (with the help of a magnifier) the wire numbers on the metal housings.
The blue plug is C1 and the clear plug is C2.
The grounds are black wires with white tracers.
C1 pin 60
C2 pins 3, 15, and 26
Ground one meter lead to the engine (the dipstick tube works well) and probe the pins with a paper clip.
The readings should be around 1 ohm.

These wires, along with 5 others go to a common ground plug on the lower front left of the engine. It is fastened to the engine with a bolt, 15mm head. It is very hard to get at and very tight. Use a 1/2" drive breaker bar, barrel ratchet and short extension with the breaker bar standing vertically between the radiator and the engine. Pull the top radiator hose back out of the way. Have a length of conduit handy to slip over the breaker bar handle.

With the bolt out you can fish the plug and wires out toward the driver's side enough to work on it.
The wires have small spade terminals on them that plug into the bottom of the connector that bolts to the engine. If you have high resistance in your blk/wht wires you will find corrosion here. Mine were bad enough I just cut the terminals off and soldered the wires to a large lug that fit the bolt.

It's an all afternoon job but by soldering and coating everything with Vaseline you will have a lifetime fix.
 

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2000 DTS 194,000 miles, 2000 DHS 203,000 miles
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Sounds a lot like the issues my wifes DHS had when I found a purple class 2 data wire broken along with a couple others in her right rear door jam where the wires go from the car to the door inside the rubber boot.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Those multiple ground connector boxes bolted to a body/engine metal points.......... there have been several problems with those over the years and the fix is as posted - install individual or common soldered terminal and bolt IT to the ground point.

One location with those multiple grounds is down in the rear fenderwell quarter cavity - outboard under the carpeting and floor panel - down in the quarter panel well. Another bad one is the ground box behind the kick panel trim on the driver's side, door jamb metal.
 

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There are actually 18 ground points on my 2000 DTS. Each has multiple wires. I pity anyone trying to work on these cars without a factory service manual. It's two volumes, each 3 inches thick.
 
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