my 1997 Infiniti J30 had the engine die at a stoplight. It turns over when I try to start it, but the engine won't start. The power windows were partly down, and they now won't go up, although the radio, turn signals and headlights seem to work fine. I tried using the diagnostic mode switch to reset the ECM but no it made no difference so far. Jumping it does nothing because the battery seems fine. I checked the fuses for the starter and related things, and they all look fine. None of the relays under the hood seem melted or bad. My OBD scanner just says "error" when I try it. I took it to a mechanic and he claimed I have to update the ECM software for him to diagnose it, and the dealers want $130 to do that. I can't find a replacement ECM for under about $170. Any ideas what could be wrong or how to fix it? Thanks in advance.
It sounds like you have a few things going on.
- If your OBD scanner reports "error", it's that your ECU isn't responding. Maybe your ECU isn't getting power, maybe it's defective.
- Your power windows being stuck suggest an overall electrical glitch in the car. Since the car is almost 20 years old, check to see that there isn't a switch (power window, power lock, etc) that isn't "stuck" and hasn't returned to center (I've seen this in a 96 Intrepid).
- Get your battery tested, make sure it's good.
- Clean your battery terminals.
- Inspect all electrical connections, especially to the ECU.
- Inspect your engine ground. They get corroded easily.
- For a replacement ECU, junkyard is always cheapest option. It will allow you to rule out your ECU being defective.
- Inspect all fuses closely.