i have a 2001 nissan sentra i resecenty had to buy a new ecm because of idle problem.?

Question

but when i replaced the computer the car ran great, but after a couple of hour the engine light came on and the idling problem started again what could be the problem.

Answer 1

Well, I'm not an expert, but what it could be is that you bought a 2001 Nissan Sentra.

Answer 2

There are several possible scenarios
1) the part failed as it was probably a rebuild ECM and even new parts can fail
2) The replaced part was only a symptom of the real problem and so whatever killed the last ECM has now claimed the new one.
3) The check engine light comes on for a myriad of different problems, some of which cause an engine to run rough. It's very POSSIBLE that a new problem has occured unrelated to the last problem. Not likely but it does happen.
4) There could be a poor ground or other connection causing loss of data to the ECM.

Whatever the case, it should go back to the shop who did the repair so that if it is a warranty issue, it can be resolved by them at little or no charge to you. Make sure you are getting a complete understanding, You cant ask too many questions and a good shop facility will take the time to educate you on what the problem is with your car.
good luck

Answer 3

You replaced only the ECM,but the source of the problem is still there!For example,the idle air valve which regulated the amount of air bypassing the throttle for engine idling can be shorted and fried the original ECM in the first place.Seen that with Nissan cars.Check all loads for short or closed circuit before plug in another one.HTH.

Answer 4

Past the 8 year 80,000 mile ECM warranty? Did you go to Nissan? I get those ECM's covered by warranty. There were recalls about the ECM case foam that held moisture and caused ECM's to fail. Replacing the computer is only part of the job now tell me what code is present. You may have another problem like P0171 lean running. Drop in to Auto-Zone and if possable write down the freeze frame data too

Answer 5

Idle control valve most likely.
I don't know the maintenance record for your car, but it might be something simple like plug wires and plugs. Maybe even something like the air filter.
Do the simple things first.

Answer 6

There is recall on the PCM's for these cars.