Hi Guys,

We have a 2009 Nissan Versa Hatchback. My wife went out to drive it today and sounds like it started fine. She got about 100 feet, and then it stalled out. Now it won't start again.

Battery seems fine. No issue turning on lights. When I put the key in the ON Position, the NATS red Security Light stays lit. After about 3-4 seconds the radiator fan turns on even though the HVAC is off. Fan stays running. Outside temp is 50 degrees. No check engine light or anything.

I tried to use both bluetooth OBD2 scanners that I have with the Torque App, but neither adapter would talk with the ECM.

Any thoughts on where to go next?

The fan means the ECM is offline, the IPDM automatically turns it on high if the ECM becomes incommunicado on CAN. The ECM fuse will be in the IPDM, that's the first thing to check. If it keeps blowing, the two most likely culprits are a warted spark coil or coil wiring, or a drive belt failure that "whipped" the wiring for the IVT valve. You can check the coils just by disconnecting them one at a time and see if the fuse doesn't blow.

Thanks! I was preparing to tow it to Nissan thinking this was a NATS problem. The fan running was the key. I confirmed with a hardwired OBD2 that I couldn't communicate with the ECM. As suggested, I started looking at fuses in the IPDM, and found the 20A fuse for EGI blown. I had a spare 15A fuse, and used that temporarily. Car started right up.

Any thoughts on what may have caused that? I also have a P0031 code now. Are O2 sensors connected to the EGI circuit somehow?

The car has an A/F up front, not an O2. The P0031 means the A/F heater circuit is bad or open, but it's on a different fuse from the ECM relay and I doubt it's related. The rear O2 heater is on the same circuit as the A/F heater, so I don't think it's even a power issue. It's possible (albeit unlikely) that the ground-side heater driver in the ECM blew and took out the ECM's main supply, but I'd check the coils before looking for anything exotic. You may have one that's about to die and heating up intermittently. Let the car get cold and then start it, then feel the coils as the car runs. If any of them heat up very quickly compared to others, that's probably your culprit. Check your engine ground with a voltage-drop test, too. Versas are notorious for dicey ground connections at the bottom end of the cable where it attaches to the tranny, and crappy grounds will definitely cause coils to melt.

So the intake manifold sits right above the coil packs, right? How do you feel them when they are sitting behind the intake like that?

Oops, forgot they're under the plenum on the Versa. For unreachable coils I usually put an ammeter across the coil fuse to see if the current is high, healthy banks usually draw no more 5~6 amps. If you find it high then it's worth removing the plenum to investigate. Dying ones will almost uniformly have "warts" in the epoxy. You can also shoot a laser thermometer in from the passenger side if you have one, or a regular thermometer with an extended probe. Bad coils will get spots that are very hot, so the car doesn't need to be running while you check, they'll hold heat for several minutes after you shut it down.