Mechanics

THE ECM ON MY LW2 NEEDS REPLACING IF I USE AN EXACT MATCH IE PART 39153242/ 0261204591 WILL IT WORK?

2000 Saturn Other • 154,000 miles

My mech told me that me saturn lw2 needs a new ecm. Ours stop working properly when it overheats. The car just stops running. We have also had issues with the cruise control and security alarm. I have found several used parts that match the part #'s exactly i.E. 9153242/0261204591 but I spoke to a local gm dealer and he told me that used parts rarely work and that they seldom can be reprogramed to match my car. They said I could spend hundreds trying to program for nothing. If I buy a used part are they really hard to program and if it is the same parts number will my car run?
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Stu0605
May 30, 2012.



What happens to the security system?Those cars are known for bad body control modules which controls the security system.I have replaced tons of the body control modules on those cars but not so many ecm. Usually the reason I have replaced ecms on those cars is for no starts. When I checked for codes was unable read data or codes from the ecm. That is the most common thing I have seen go wrong with ecms. Does the gas gauge temp gauge power door locks keyless entry ever become inop?Also any other things become inop?Any codes in the ecm?

Saturntech9
May 30, 2012.
Have had problems with the cruise control not working and the transmission shifting hard then it stps when you shut off and restart the car. My mech said he tested the ecm and it was throwing some crazy numbers ie wrong rpms showing 10k when it was idling at 6 or 700. When we had issues with the transmission we put the car on meter and there were no codes

Tiny
Stu0605
May 30, 2012.
The hard shifting is a common issue on those cars usually caused by a bad pressure control solenoid in the valve body. It would be nice to know the other codes you have. Usually when you get the hard shifting it will set a code P1811. So the guy working on the car thinks the ecm is bad because the engine rpms are reading the incorrect rpm readings?Those cars are also known for bad crank shaft position sensors. Which would explain the rpms from the engine being off dieing while driving then not starting till it cooled down. Any way you could get me those exact code numbers you have in the computer?That way I can tell you what I think is going on with the car.

Saturntech9
May 30, 2012.
When the car dies It has been put on a monitor and we have been unable to read the codes as no codes came up. We have not had any issues with the guages not working right ie fuel or temp. The door locks work fine but the keyless entry is not working as the fobs battery is dead. My mech said he tested the ecm and he is sure that is the problem. My question is other than buying the exact used part. With the matching part numbers what more is needed to replace the unit? Can I just buy the same unit from a matching car with the same accessories?

Tiny
Stu0605
Jun 3, 2012.
How did he test the ecm?There is no test for the ecm that I know of and I have been a factory trained saturn tech for over 16yrs. What I do is rule everything else out to find a bad ecm. So when it dies and wont start the scan tool will talk to the ecm?I have seen bad crank shaft sensors being bad and no set any codes before. So do you have to let the engine cool down a certain time period for it to restart?If you have a scan tool handy that will read live engine data when it wont start you crank the engine while watching the scan tool to see if the rpm readings go up while cranking the engine over.I just don t want you to replace the computer if it doesnt need it.I have also seen those car have the main relay go bad and cause random crank not starts dieing while driving and then not starting.

Saturntech9
Jun 3, 2012.
Ok what I would like to do is start from square one. My 2000 Saturn lw2 suddenly dies while driving. Approx 2months back we had the oil cooler replaced. When we got the car back it ran great. We replaced the plugs and the performance and mileage increased a great deal. About 2 weeks after getting the car back the service engine light and check engine soon light came on and the car started shifting roughly. We immediately took it to our tech. He put it on his meter and no codes came up. None. We restarted the car and test drove it and it was fine. Shortly thereafter it would run rough and die for no reason. Our tech again looked at it and told us it was the ecm. After speaking with several techs I first decided to clean the connections to the ecm. This had no effect as the transmission shift problem occurred again that same day. I will go to a local auto parts store to see if there are any codes and post on here asap. Is there anything else I should look for?

Tiny
Stu0605
Jun 13, 2012.
Oh one more item the check engine and service engine lights came on when the transmission shift issue happened but are not lit now.

Tiny
Stu0605
Jun 13, 2012.
Your probably going to see a P1811 for the transmission hard shift. If so its probably a bad pressure control solenoid very common on that car. It really sounds like a bad crank shaft position sensor as far as the dying and wont start till it cools down. Thats another common issue on those engines. They dont always set a code though. Let me know what the codes turn up.

Saturntech9
Jun 13, 2012.
Ok after doing some homework and talking to a few saturn owners I replaced the cps. The car is running great but I have a new problem. When the brake pedal is depressed I cannot rev the engine at all. It will rev in park and nuetral but when in gear with the brake pedal applied when you step on the gas pedal nothing happens. Is this normal in a 2000 lw2?

Tiny
Stu0605
Jul 11, 2012.
Glad it took some saturn owners to convince you to replace the crankshaft position sensor and not a factory trained saturn tech lol. You found the problem and it was what I was talking about all along like I said I worked for saturn for many years.I have replaced a ton of those crank shaft position sensors for that same issue. As far as the throttle being disabled while braking its one of the many safety features of the throttle by wire system. Remember all the toyotas that people said acellerated on there on etc?Those were throttle by wire systems also. If there is a problem in the throttle by wire system it will set a code in the ecm.

Saturntech9
Jul 11, 2012.
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