Question about 2003 Cadillac CTS

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

My ECM was replaced on my car. It is still in the shop and they told me the starter is going out because it doesn't start all the time. Could that possibly be from the ECM and not the starter.

Posted by Shawna on


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Col Dana Gillespie

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  • 88 Answers

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.

Posted on Oct 27, 2012


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  • 113 Answers

SOURCE: I have an cadillac Cts 2003 with starting problems

the plugs are the problem, they become unable to ignite all the fuel when in idle, so that they get wet and won't give any spark until dry. try to replace them. if there's no difference the problem is at the admission system(fuel pump maybe)

Posted on Mar 13, 2010



  • 19396 Answers

SOURCE: 82 Cadillac ECM wiring diagrams/ troubleshooting

if a new ECM had blown shortly after replacement, the problem is likely to be in power wiring to ECM.
Check all battery wiring to the BCM/ECM for bad connections and shorts, (shorts, corrosion etc.), and test all voltages to ecm.
Check for short to ground in ckt491 (Orange wire), check for Open or Short to Ground in ckt 526 (Brown wire).

Posted on Jul 07, 2008



  • 546 Answers

SOURCE: The AM/FM radio in my 2003 cadillac CTS faded to only static

check antenna cable connections at radio & antenna.suspect power antenna if equipped.

Posted on Sep 30, 2009

john h

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SOURCE: 2003 cadillac cts v6 3.2 liter. white smoke

u have a leak in the heater core the oily smell and mist is anti freeze sounds like a small leak because usually u would have a wet floor if it was large -two choices check and repair as necessary the core or can use an additive with a stop leak they usually work well on small leaks

Posted on Dec 14, 2009

Salvador Quintanilla

  • 1608 Answers

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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1 Answer

How do I replace defective ECM?

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Regards, Jay

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