ECM means time limit to Nissan ownership?

Sorry you are having this difficulty, sounds very frustrating. fyi, another company that repairs car computer modules is called “module master” . I think they specialize more in ABS modules, but they may service certain ECMs too. Other posters have said they got some good info from them just by calling. One problem you may have is that Nissan modules aren’t as commonplace as others like Honda or Toyota, simply b/c Nissan doesn’t sell quite the same volume of cars.

Playing Devil’s Advocate for a moment I might add this.
A car manufacturer does not build a new car with the intent of support forever. This is true of all of them. Many parts (ECMs included) are provided by an outside source. The parts source dries up over time.

This leads to the dealer in many cases not being able to obtain the needed part from the car maker.
In some cases the car maker may not be able to obtain the part from their supplier over something which has been obsolete for a few years. The supplier has no intent of opening up a production line again at tremendous cost to turn out a comparative few parts.

In some cases this may mean a nationwide computer search in the hope that some dealer has the part collecting dust on a backroom shelf or it may end up on backorder. Backorder means maybe a week, maybe a month, maybe never.

No one has brought this up yet, but the dealership could be wrong in their diagnosis. We are all assuming that they are right, but what if they aren’t? Maybe the OP should take the car to a local AutoZone and have the codes read and report the code here. Be sure to report the actual code, not the diagnosis, just the code. P0xxx format.

I agree with keith as I’m not a huge fan of a failed ECM diagnosis. Granted, it happens but should be a last ditch effort.

Guys, remember that guy a few weeks ago . . . ?

He had some kind of Nissan, with a bunch of oxygen sensor codes

We posted a link to a technical service bulletin, which concerned a bad ground

The fix was just a few bucks

He reported back that it solved the problem

I wonder if it might also be something simple, in this instance . . .

I suppose since the OP is dead set on replacing the computer, that getting the actual codes that are coming up is a forlorn lost cause?

No one has brought this up yet, but the dealership could be wrong in their diagnosis. We are all assuming that they are right,

I count three people before you that mentioned that possibility, including myself.

You guys are right about the second opinion from someone other than the dealership. I haven’t headed down this path yet because I’ve been working with the folks in the service department through this entire ordeal. They have proven to be reliable and dedicated. The fail code for those of you who have brought it up and are interested is P0031.

My experience has been that if the sensor has been replaced with a factory part and the wiring hasn’t been chewed up it’s the ECM that is at fault. This was a fairly common problem to have been fixed under the 8yr/80,000 mile emissions warranty. I am a little surprised that a part is not available through Nissan but perhaps there’s a shortage of rebuildable units or some other supply issue. Anyway, at the age of your car there are lots of aftermarket options available to you.

Heater circuit voltage excessively low. I would hope the possibility of a popped fuse or scaled wire connector has been considered before condemning the ECM.

I would check the integrity of both sides of the heater circuit, including all the way back to the PCM connector shell (if it goes there), or to whatever source (relay, etc.) it has before condemning the PCM. Hopefully the dealer did this. I would certainly ask them.

While a shorted heater may have damaged the driver circuit in the PCM, I would definitely check the circuit first.

This is interesting because it involves the front sensor. This generation of Sentra’s have an issue with this happening on the rear sensor because the connector to the rear sensor is located in an exposed area under the alternator. It gets full of water.

I don’t know if the same thing can happen with the connector to the front sensor but it might be worth looking into. If changing the sensor causes a temporary fix, it could be a corroded or dirty contact in the connector.

MAF cleaner makes a good contact cleaner, as does good old rubbing alcohol (91% or higher). Disconnect the sensor and either spray out the connector or clean the contacts with alcohol and a Q-tip (spray works better).

If you have a Radio Shack near you, they carry (or used to carry) a very good spray contact cleaner.

One simple test is to use a DVM to measure the heater circuit voltage. Measure it right at the probe connector, with the connector still plugged on to the sensor. Does the meter reading show it actually measures a lower voltage than it should?