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PCM replacement


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I had my 2000 Eldo in the shop for a theft deterent roblem car would not start. The mechanic said that the front bank was reading eratattic from the O2 sensor and he said the PCM should be replaced before the cat gets destroyed because of runnning rich. I found a PCM for my car, but when I install it the car will not turn over, I put the old PCM in and it starts. I get a theft deterent problem car may not restart with the replacement PCM. Do I need to take it to the dealer to get it programed for my car?

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I would put the old PCM back, drive the car for a day, and run the OBD II codes myself. Here's how:

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Problem is...the major components can be programmed one time. They are VIN # sensitive.

I grabbed this off our site. It's a GM TSB.

Class 2 Serial Data Communication allows control modules (i.e. the Powertrain Control Module (PCM), the Body Control Module (BCM), the Dash Integration Module (DIM), the Instrument Panel Cluster (IPC), the radio, the Heating, Ventilation and Air Conditioning (HVAC) Controller, and the Sensing and Diagnostic Module (SDM) to exchange information. This information may be operational information or identification information. Among the identification information exchanged and compared within these modules is the Vehicle Identification Number (VIN). Typically the one module, the master module, broadcasts the VIN and all the other modules compare the VIN stored within itself. When the broadcast VIN does not match the VIN stored within the SDM, the following actions occur:

• DTC B1001 Option Configuration Error is set and deployment of the airbags is inhibited.

• DTC B1271 or a DTC B1780 Theft Locked.

The VIN information is also used by the radio. When the VIN does not match the VIN stored within the radio, DTC B1271 or DTC B1780 is set and the radio is inoperative.

Additionally, the master module will compare the SDM's part number (last four digits) to determine if the correct SDM is installed in the vehicle. If the SDM is the wrong part, a B1001 will also set.

This situation may occur when a vehicle is being repaired. When a PCM or a body control type module is replaced, the VIN information must be programmed into the replaced (new) control module. A module which has had VIN information entered into it (for example, one taken from another vehicle) cannot be reprogrammed. VIN information can only be entered into new modules. The ignition must be ON in order to program the control module. Since the VIN information is broadcast when the ignition goes to ON from any other ignition switch position, DTCs may be set in the SDM and/or the radio. Therefore, always follow the specified control module replacement procedures.

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From the original post, I'm not at all sure that there is anything wrong with the original PCM. If it is running rich, it's probably not the PCM. If the PCM goes bad, usually the car won't run. If it is running rich, you will get an OBD code, and the Check Engine light will come on. If the codes don't bear out what the mechanic is saying, get another mechanic.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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To answer the original question of the New PCM..... Yes, the PCM will need to be programmed with your cars Vin # or it will not run. Dealer costs about $150 bucks. I do Agree that the I would check to see why the car is running rich, and how do you know for that matter that it is running rich? Check the codes and start there...

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This is what the tech had put on my bill.

multiple issues no crank,no PCM communication,perform diag,found no battery power to PCM,circuits good,found 50 amp fuse blown.install new fuse,ok,ACcompressor relay pulled,fuse feeds comp circuit, relay in cup holder,comp possible cause,start vehicle, multiple DTCS and running poor, misfires accumalating on cyl3,install good coil cassette no change,RNRplug,plug carbon fouled,injector ok.Replace all plugs install proper plugs, run vehicle,ok,monitored system, found RHfront O2 sensor sticking at sporadic values, test circuits,perform diag,circuits test good, test PCM responses, no changes, faulty PCM indicated per diag, declined, converter damage may result due to nature of failure.

The codes I get are P300 random misfire, P0171Fuel Trim System Lean Bank 1

P1133 - Heated Oxygen Sensor (HO2S) Insufficient Switching Bank 1 Sensor 1

B1314 - Evaporator Inlet Temp Sensor Open Circuit

I have the AC pulley disconnected with a smaller serpentine belt, because my AC doesn't work the same reason the AC relay was not in. That I will need to fix because it is getting to summer, That also makes me question the computer because last year when the AC was worked on the mechanic said to take it to Cadilliac, because he replaced that sensor, vacuumed the system replaced refrigerant to proper level and the compressor would still not start. He said the computer has locked out the compressor but can not figure out why even though he replaced the sensor and checked pressure.

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And these codes also

U1152 - Loss Of ACM Serial Data Communication

U1152 - Loss of Data HCM

I do get times when the engine will run rough, a quick stab of the pedal clears it up usually with a puff of smoke out the tailpipe. When it is idleing and it starts a miss you can smell the excess fuel.I had replaced the plentum it had a tear. I thought I had the misfire cured but obviosly not because it came back just not as severe or often.

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I'll say it again.

Based on the GM TSB listed above. PCM's and other major components can be 'programmed' one time with the VIN #.

Even if you have a Tech2, and a GM Techline PC. You cannot reprogram a used PCM.

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  • 6 years later...

You know. This makes me think about something.

What happens with people like us when those modules are no longer available?

For good example I have no plans in getting rid of my 97 Seville for awhile. If one of the modules goes bad the car is useless?

I am sure we all think of this as our vehicles become vintage.

I have a 25 year old truck and it will run forever without needing any special programming.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Planned obsolescence?

Anyway...it already happens everyday. Try to find a new air bag SDM module for something like a 2005 Hummer.

Kind of unrelated...there is a push by car manufacturers that you really don't even own the car. Your just using it for 'x' amount of years. All the software and code etc in it...still belongs to them.

http://www.extremetech.com/extreme/203913-general-motors-john-deere-want-to-keep-tinkering-self-repair-illegal

Maybe it wont be long....buying a car may be like buying a cell phone. Free every 2 years with a new plan.

Why else would Apple and Google want to make cars? 6% margins in the good years...bleed money in the bad years under the current scenario.

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It's the aluminum electrolytic capacitors i worry about. Keep the car out of extreme heat as best you can. It's expected that these things fail as they get old. All my capacitors are 19 years old, and i'm not going to loose sleep over it, as i have a good eye to visually detect failures, and i am very good with a soldering gun.

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  • 3 weeks later...

Actually you can get your pcm re programmed or send for a remanufactured one :D instead of buying a whole new one jejejejej Sorry I'm also kind of new to this whole thing. But I really thought you can just get a new one and replace and that's it. but those dang things cost a lot <_<:D I was looking for a new one cadillac pcm too since my car shows the check engine light, and my mechanic said that we can get a re programmed one or have your old one reprogrammed for a cheaper price on ebay, solo pcm, and re-manufracturing companies :hatsoff:

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