Question about 2003 Cadillac CTS

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How to replace the ECM on a 2003 cadillac cts

Trying to replace the ecm on a 2003 cadillac cts

Posted by Dale Jackson on


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Michael Carroll

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Unblot it , unplug it and replace . then take it to the dealer so they can remarry all the other modules to the pcm .

Posted on Dec 16, 2014


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SOURCE: Can you guys please help

should be on the left toe kick pannel

Posted on Feb 26, 2011


Salvador Quintanilla

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SOURCE: ECM replacement for an '05 Cadillac CTS 3.6L

I was reading through the replacement procedure for the ecm in your vehicle.Here`s what I may use a used ecm but it does have to be reprogrammed to your vehicle and it can only be done at the dealership.This I know because I worked at a Cadillac and G.M. dealership.I worked at a dealership for 16 yrs.The other thing is you don`t` need the vehicles vin that the used computer came from.The only one you need is your vin number.This number has all the information that your car is equipt with.The used ecm will have the other vehicles fuel continue password so the programming will put in the fuel continue from your vehicle.The other thing that needs to be programmed is the engine oil life and the transmission oil life or they revert to 100%.Then an idle relearn procedure will have to be performed.The only thing any other shop can do is get the codes or clear the codes.But they can not program a computer.Only the authorized dealerships have this software.Hope this helps clear up your any questions.Good luck.

Posted on Dec 22, 2009

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SOURCE: 2003 CTS cadillac, 135k miles. The

I have the same problem. The dealer has installed a new throtttle body, then a new ECM. I STILL have the same problem. The dealer has no ideas and now wants to charge me to see if my valve seals are leaking. Sure, after $2,400 I'm going to let you pull the top of the engine off to check my valve seals.
One mechanic (non-Cadillac) feels the battery ground wire is corroded and should be replaced so that's my next step.

Posted on May 25, 2011



  • 3018 Answers

SOURCE: How do I find thw pcm/ecm on a 2006 cadillac cts

  • Remove the left few plastic pins holding the belly pan on, remove bolt holding cover for box holding the PCM and pull it down (sometimes it falls down so be on the look out for this too. Remove the 2 bolts holding the harnesses on.

The PCM is indicated in the diagram (#1)


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  • Hope this helps and thank you for using FixYa.

Regards, Tony

Posted on Oct 08, 2011

Ken Hiester

  • 31 Answers

SOURCE: how can I fine the ECM reset fuse in my 2005 cadillac cts fuse box

If it is in the fuse box it should be labeled PCM. If it isn't there it may be in a wiring harness under the hood.

Posted on Oct 14, 2012

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How do I replace defective ECM?

The Engine Control Module should just pull out and unplug. Not sure where it is located on the CTS but my caddy has it in the engine bay just behind the left headlight. It is in a plastic box that snaps into locating holes. the box opens up and the ECM can be unplugged and removed.

Dec 24, 2015 | 2003 Cadillac CTS

1 Answer

Cadillac cts 2003 3.2l engine the timing belt jumped time i replaced the set it back on the timing marks an it didn't start i a code po 341 so replaced the camshaft position sensor didn't start

The same thing happened to my 03 CTS. The camshaft position sensor code is often thrown for a variety of reasons. In my case somehow the ECM went when the timing belt jumped (after the serpentine belt broke). It was a bear to diagnose but after installing a rebuilt ECM it runs great. (Don't make the mistake I made: the cylinder head gaskets will fit nicely on either side but if not placed on the correct sides you'll block the single oil port which provides engine oil to the head)

Apr 04, 2015 | 2003 Cadillac CTS

1 Answer

Will a 2003 ecm work to replace in a 2004 Cadillac CTS?

No... All ecm (s) are make model, year, and vin specific. They must be flashed with the correct information which includes engine, accessories , sensor, etc for the specific car... The car will not start.

Feb 24, 2015 | 2004 Cadillac CTS

1 Answer

2003 cadillac cts after the ecm was replaced the car will not start all the time

If the ECM was replaced properly it have no efffect on the engine starting. If the starter is turning the engine over then it's doing all it was designed for. I think I would get it out of that shop. I smell a rat over the internhet.

Oct 27, 2012 | 2003 Cadillac CTS

1 Answer

2003 Cadillac cts service engine light & traction control light don't work. I just purchased this car yesterday and noticed that both the MIL and the traction control lights are not working. The...

Unfortunately, is either a faulty ECM or with the ECM wiring. Check the connectors at the ECM with the negative battery cable disconnected. Are there any other DTCs?

Jul 12, 2017 | 2003 Cadillac CTS

2 Answers

I have a cadillac 2003 cts car and come out theft system how can desactivated can you help me please

If your portable remote is not work , you may need to replace the battery with new one. If it not work , you need to disconnect power supply into your security system / immobilizer / anti theft.
Regards, Jay

Feb 19, 2011 | 2003 Cadillac CTS

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