00 C70 electrical/running issue

davidsimoncincy · Post by **davidsimoncincy** » 27 Jul 2015, 06:56

Good morning all, I am stumped by my C70 convertible...I have only owned it for about 60 days, and it was running fine...171,xxx miles with some service history. SRS light is always on. I hit a big pothole about 2 weeks ago, didn't think much of it until the next time I started the car. It was surging, ABS, Traction control and brake lights on, it was only about 3 miles to home, so I just kept on going. The odometer went to ------- then the speedometer and tach flatlined. Headlights were fine, /c was still blowing cold. I got home, turned it off, restarted it, all was well. Drove it for 2 days, everything was fine.
Since then it will run fine for about 10-15 minutes, then it will stumble/misfire for a second or two, maybe once a minute. Then, the ABS and brake light will come on. The odometer MAY go to dashes ----- and if it does the speedometer and tach MAY flatline. The traction light has not come on since the first episode, which is also the only time it acted weird on a cold start. If I turn it off and restart, it acts normal for at leas a couple of minutes, then the same process starts again.

I replaced the ABS module with a rebuilt unit, which didn't change a thing, except cut up my hands trying to get to it. The battery tested good, but with a low charge, per O'Reilly's. I am getting 12.58 volts when the car is off, 13.88 volts at idle, 13.8 volts at 2000 RPMs. No voltage drop from either battery cable.

Any thoughts on my next move?

Sommerfeldt · Post by **Sommerfeldt** » 27 Jul 2015, 10:10

Hey there. Any number of things could have been knocked loose if that pothole was harsh enough, but start with the basics.

Diagnose first, before you start throwing parts at the problem. Read your codes - they don't necessarily tell you what's wrong, but they'll tell you where to look. From your description, I'm inclined to say it's a communication issue, and while it seems exceedingly weird (never heard of it happening, really...), check that all ECU cables are secure and connected, connectors are snug, etc. But first of all, read your codes and post'em back.

Also, welcome.

- S