ECM Repeatedly Failing

[artsenn]

I own a 2000 LeSabre 3.5. Over the past 3 months the ECM (is that engine control module or electronic control module?) has failed twice. This time the mechanic replaced the Camshaft Position Sensor thinking that could be the only thing that could make the ECM fail. Does anyone have any idea of what could cause this and do you concur that changing the CPS will fix the problem?

Thanks,
Art

[BNaylor]

Welcome to AF.

Has the PCM failed twice and been replaced or are you just getting odb-ii DTC error codes triggering the SES/CEL light.

It would be helpful to post the DTC error codes from a scan and the mileage of your car so someone can weigh-in to help you.

BTW - Your Le Sabre has the Series II 3800 engine. Also, what are your symptoms or driveability issues?

[artsenn]

Thanks.
I don't have the codes. The ECM has been replaced twice. The car has 55,000 miles. The symptom is a badly misfiring engine. The check engine light comes on in a short time after the misfiring begins. It's still driveable though and I am able to get it to the shop.
Art

[maxwedge]

Originally Posted by artsenn

Thanks.
I don't have the codes. The ECM has been replaced twice. The car has 55,000 miles. The symptom is a badly misfiring engine. The check engine light comes on in a short time after the misfiring begins. It's still driveable though and I am able to get it to the shop.
Art

As Bob said the codes are important here, it does not sound like a pcm related problem, see if you can get it scanned for the codes and post back.

[artsenn]

Excuse me but I am a rank novice when it comes to modern automobile engines. My first reference was to an ECM. I assumed this was the same thing as the 'Ignition Module' which is what has been failing. You keep referring to a PCM. Is that the same thing as the 'Ignition Module'? I will contact the shop that has been fixing this problem to get the codes as soon as I can. Thanks again for your help.
Art

[BNaylor]

The PCM is the powertrain control module. For odb-ii cars we call it a PCM. For odb-i cars it may be called an ECM/ECU. Your car is odb-ii so it is a PCM.

The ignition control module (ICM) is the module underneath the three ignition coil packs and this component helps generate the high voltage to the spark plugs.

If the codes are available that will help us be able to provide the proper guidance.

[Bassasasin]

Interesting Posts... I have noted some ICMs Ignition modules have shown some small improvement that the one replaced seeming to repair symptoms for a while. Also PCM (computer behind glovebox) have made some improvements . BUT all temporarily. Im not sure but I think it may have been the RESET of the system that caused the temporary improvement or the small diffferences in the newer replaced units were more able to see the sensors. Connectors get jiggled and cleaned somewhat and connections improve.

Classicly the Crankshaft sensors have been failing moreoften on engines over 100K miles and caused drastic intermittent stops of the engine and occasionally throwing camshaft codes. Ignition modules were suspected and found not the solution. Rough running is from the coil packs and wiring. Occasionally but even less often wiring has failed at the sensor or Ignition Module connector.

PCM modules have failed but have had help failing, bad grounds, bad voltages from a alternator, and sometimes show other symptoms of other circuits failing like cruise control.

Its good to note that after a predetermined time the engine shifts between open loop or closed loop which means it uses certain sensors to evaluate its running parameters like cold start or hot engine run. The O2 sensor must be hot enough to evaluate mix and the PCM determines its up to temp before it uses it. Disabling some sensors can force a open loop run which may be more dependable during problem times. Handy when a dependable car with a check engine light is more important for a time than a fuel efficient one.

Good Luck Buick ites.