C4.Taylor

My 93 has been running beautifully for about 6 months now until yesterday. I was preparing to go on a long road trip and naturally stopped at a gas station to fuel up and check my tire pressure. But for some odd reason after I filled my tires to the specified PSI my car ran like crap. Similar to the way it felt before I installed the new opti a couple months back. Then my 'Service ASR' light came on. I drove it to the next parking lot where it was running fine again. Turned the ignition off and tried starting it again and it wouldn't start. It was cranking just fine but would't run.
So I called for help and by the time it got there my battery was dead. We jumped the car off and it purred like a kitten and no service asr light. Drove it home fine. Tried to start it again and that light was back along with the service asr light. Pulled the ecm codes and got code 41. Im thinking it's a loose connection somewhere. Can someone guide me toward the light and help me revive my sweet corvette!?

C4.Taylor

The only reason I mention the tire pressure is because I found a thread that had a guy saying his car wold run like crap and give him the service asr light when one of his tires was below 20 PSI and when he aired it up it ran fine. He says he did this like 4 times and it worked every time. I know sounds crazy but just thought I should mention.

antfarmer2

41 Loss of ECM serial data communications

C4.Taylor

I got that far, but what's next? After reading through multiple threads it can be a list of things. From what I've read I think I need to replace my ECM but I don't want to jump to conclusion.

antfarmer2

Any power to the coil or spark from it

stingray71

Since your battery died so suddenly and you had to jump start it, I would wonder about the alternator. Is the battery getting charged properly when it is running?

C4.Taylor

I haven't had a chance to get a multimeter or test light to do this yet, but when I do I'll check back.

And I have a brand new alternator on the car but something has been draining my battery. If I leave my car parked for about twelve hours or longer I need a jump to start it. I haven't had time to track down what's doing it. And recently I've had to jump it off more frequently because I've been using my fiancee's car. And I'm actually starting to think that this my have had something to do with ruining my ECM.

oldpro

it might just be as simple as you might be losing a cell in your battery . I had a battery go bad after just six months . might not be but why not ck easy stuff first and go from there.jmho. also ck the battery connections and make sure they are tight

1994DelawareCoup

Check the fusible link as well. Behind the battery and the fuse box on the fire wall. It's just a piece of higher gauge wire designed to melt before the wire harness gets damaged. It's orange I'n color. If it melts the battery does not charge. RPMs drop electric drops car runs like crap. Mine went because of the alternator. Volt regulator went wild and sent a surge. Fusible link melted just like designed.

C4.Taylor

Okay so I finally got a chance to jump my car off this morning and it started and is running just fine. I still have the service asr light though. I'm going to take a chance and drive it to work and hopefully if it makes it home I can start doing some diagnostics. I bought a test light yesterday from Harbor freight.

I checked the fusible link and it looked perfectly fine. (The two orange wires correct?)
And oldpro you may be correct about the bad battery but I have bigger fish to fry with this possible bad ECM and a bad battery wouldn't be giving me the service light.

1993C4LT1

Can't you tap the ECM to see if it's bad, while the engine is running? I remember reading on here that if you tap the ECM, and car turns off, ECM is bad.

C4.Taylor

Okay so I took my battery to O'Rielly's to test my battery.. and like oldpro suggested I indeed had a bad battery. Installed the new battery and the car started up and ran perfect, along with no 'service asr' light. I haven't driven it yet but I know the light can still come back on after the computer resets. Crossing my fingers.. If it was just the battery I will feel dumb. But why would a bad battery give me a 'service asr'? And make my traction control not work anymore? So I'm still a bit sketchy.

MavsAK

Not enough power to run everything in the car. A bad ground will do the same things.

oldpro

glad I could be a help owning a zr1 for over 10 years ,I have seen just about everything . sometimes it can just drive one a little nutty

C4.Taylor

Woke up this morning car started and ran just fine with no asr light. Car started and got me half way to work before the light reappeared. Got home turned off the car and it didn't start back up. Just cranked but wouldn't start. Back to square one.

C4.Taylor

So I found this on a post from 2004...
A serial line data loss can be caused by:
1) Serial line shorted to ground
2) Serial line open
3) No data being sent

Since there are supposedly two wires in parallel, it is unlikely that the line is open.

If your vehicle is like my '92, you can have four computers communicating on the serial line:
1) ECM
2) CCM
3) ASR/ABS computer
4) C68 Electronic climate control

Your car can run with only the ECM and CCM connected.
By disconnecting the ASR/ABS and C68 climate control connectors, you can eliminate them as being the problem -- if the problem still exists, this will leave only the ECM and CCM or the serial link itself as the problem. My problem was the ECM.

Tom Piper

What ASR connectors is Tom talking about?

C4.Taylor

Well I disconnected the ASR unit under the hood from the ECM. This wire is also attached to the master cylinder and something else underneath. The car started right up and ran fine, but the light was still on. When I reconnected the unit the car started again but the light went away... Do I need A new ASR?

C4.Taylor

It wasn't the asr unit. I guess that situation was just a coincidence. My ignition coil is getting spark and has the correct resistance.

C4.Taylor

Problem Solved! It was my ECM. A mechanic plugged it to a computer and it told him I had a bad quad core driver. I sent it out to get rebuilt once to a place called "Klein Bottle Computer" and they returned it saying it was "damaged beyond repair." Total BS because I sent it to "Davies Corvette" and they were able to repair it and it cost me $300. Totally worth it since this ECM is impossible to find these days. I hope this helps someone because nowhere else has anyone been able to fix this particular issue or at least post about it.

1993C4LT1

Hey, glad you shared the problem with us Hopefully this will help someone in the future. Now, go cruising