2001 Chevy Prizm not starting - intermittent, possible cause found?

Have a 2001 Prizm with 120k miles on it. Just had the recommended 120k service done a month or two ago (local shop that has been reliable to me) and they commented on how mechanically solid my car was.

Thursday drove to work like normal. When it was time to leave, car wouldn’t start. No dash lights, nothing at all when I turned the key. Got a ride, came back later that night and jumped it and it started right up (didn’t wait at all, but I also didn’t check it before hooking up the cables - it might have started without a jump). Radio had reset and so forth, but it was running.

Drove Friday, it was fine.

Car sat all weekend. Monday morning, dead as could be again. No dash lights when I put the key in, nothing when I turned it. Maybe a single click, but nothing more (can’t remember for sure).

Drove wife’s car to work. Came home Monday afternoon and the car started right up with no problem. Was curious if the battery voltage was low or anything, so I turned the car off, hooked up my bluetooth OBD reader (generic ELM 327 off ebay), and tried to start. Car was dead. Unplugged the reader, still nothing.

Took the battery out and ran to the store, assuming a bad or weak battery. They tested and said it’s completely fine. Went back home, hooked it back up, car started right up.

So now I’m suspecting something’s up with the ELM327… I just got it last week, a few days before this all started. Had it hooked up all week long and didn’t unplug it till the first time the car wouldn’t start. Didn’t plug it back in till Monday afternoon’s issues.

Could a flaky OBD reader cause these kinds of issues? Anything else I should be checking, or do you think I’m ok as long as I toss out that reader? When I was using the reader last week, it seemed to be reading everything fine and sending the data over to my phone. When the car was dead each time, it acted like the battery was completely disconnected - radio reset, NO lights, etc. Could something with the OBD reader mess up the computer and make it act like that, and then a little time lets the computer reset or something?

If the car has no power the computer has no power and therefore the OBD reader has no power. Sounds like corroded battery terminals or bad ground was your problem.

When I pulled the battery, there was minor corrosion but nothing too bad. Everything seemed tight and solid.

And if it was corrosion, why would the “no power” problem go away just sitting in my driveway all day, and go from starting to completely dead in seconds when I plugged in the reader?

  1. Check all battery connections and cables. You’re saying nothing has electricity when this happens?
  2. Possibly the ignition switch
    3… If other things have electricity (radio, lights) then it could be bad starter solenoid contacts - has the starter ever been replace? Toyotas are know for this problem.

If it happens again I’ll troubleshoot a bit more, but there was no power that I could see - stuck the key in, no lights on dash. Didn’t look if the interior lights came on when I opened the door, but I do remember the power locks didn’t work.

I DO know when I plugged the reader in it had power (at least at first - dunno if it had power when I tried to start the car)

Is it possible (I’m more of an IT guy than car guy) that something’s defective in the OBD reader, shorting out the ECU and temporarily killing the car? Then after a little time the ECU resets and all is well?

Well, anything’s possible, but that seems unlikely.

@timropp i agree with @texases

sounds like your ignition switch is failing

If it’s a bad ig switch, why would everything have reset each time it died? Radio presets lost, etc? It ACTS like the battery was disconnected.

That’s why going through all battery connections and cables (they can corrode internally and still look OK) is step 1. You might even have an intermittent ‘open’ inside your battery.

But if all that checks out OK, then the ignitions switch is worth a check, lots of circuits go through it, if it’s bad it’s possible it could cause your problem.

Do you hang a heavy key chain from the ignition key? That can cause problems over the years.