[vsanjay]

About three days back while reversing my 2002 Nissan Sentra (Automatic) the entire car shook and shuddered really bad. When I put it in Neutral and then tried reverse it worked fine.
A couple of days back, after returning home, I noticed that my car started revving around 2000rpm in idle (Neutral or Parking). I was very tired and left it for the day. The next day when I started it, it did the same thing. Now when I stepped on the gas pedal, the engine acted like it was dying. Nevertheless, I continued on my trip to the bank when the problem got worse and the car just stalled, and the Service Engine Light turned on. I switched off the ignition, and after a few seconds turned it on. Luckily it started, and I made my way to a car mechanic.

I was dropped at home, and the car was with the mech. for 2 days. He replaced the Idle Control Valve, and the TPS. He called me up today and said everything was fine and I could take the car. I went there, started the car, and went to a gas station. After filling up, I turn the engine on and the same story repeats. This time around, the car idles above 2000rpm, and is steady there. I couldn't even move the gear stick from idle.

I leave the car with him again. He removes all the sensors and refits them and seals them. He takes it to the Nissan Dealer so he can program the computer to adjust to the new Sensors.
The Nissan dealer is unable to feed instructions to the computer and tells the Mech. that the PCM needs replacement.
I just want you guys to let me know if all these pieces of info. fit together.
Also let me know if buying a used PCM from Ebay or something would be a good idea. And if somebody does one a spare one here?

 

[Premo103]

dang. i have the same problem right now. Nissan Frontier 2008

 

[rogoman]

One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores. Also most auto parts stores will perform an ECU code readout free of charge. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM from this web site: https://diyservicemanuals.com/. The section EC.PDF is the one you need to read.

The high idle can be caused by a defect in the throttle-by-wire system or the following needs to be performed:

“Idle Air Volume Learning” is an operation to learn the idle air volume that keeps the engine within the specific range. It must be performed under any of the following conditions:
● Each time IACV-AAC valve, throttle body or ECM is replaced.
● Idle speed or ignition timing is out of specification.