I originally had this posted in the wrong forum....sorry

We've had our 98 coupe now, for about 2 months.This forum has been very helpful to trouble shoot and fix several things that need fixin'. But it also has brought to light, several things that I may or may not have to worry about. I have seen so many posts about having to tow the car to get it repaired (for various reasons), that I am concerned that this car will eventually leave me stranded someplace. Yesterday on startup, the "reduced engine power", "Service traction control" notice came on the DIC. and I pulled the codes. The only code that was current was C1278..TCS temporarily inhibited by PCM. This is the second time in as many weeks that this has happened, although the first time it happened, my wife had the car and also got the "wait ten seconds, reinsert key" message too. I did not pull any codes at that time. The factory recall has been done on the CLB, and I am not to worried about that at this point. I cleared all codes and am going to wait to see what happens again so I will have clean codes to work with. I really want to enjoy our car, but if we are constantly worried that it will just "die" at will, it kind of takes the fun out of it. Maybe I have too much information...is that possible? And final question, what is the TAC module?

 

TAC = throttle Actuator COntrol module. It is located on the side of the PCM behind front pass wheel well. are you sure this is your only code?

 

It was my only current code. There were other history codes that were there from the previous owner (that I had viewed a few weeks ago), but didn't clear. Now, I have a clean slate to start with. If it does it again, at least I know that all the codes I see will be recent. When I cleared all the codes, the car now runs properly with no check engine warnings, but I kind of feel like I am waiting for the other shoe to drop. KLOP!

 

I too had a 98 MN6 Coupe that was the CAR FROM HELL!!!!! I got left stranded on the side of the road NUMEROUS times. Worse yet, when your in REDUCED POWER MODE, it is hell trying to drive down the shoulder of I-95 doing 6 MPH.

Not to get you deeper in the dumps but there is a very BRIGHT side to this story!

There are TWO things that can cause this problem. One is corroded Chassis Grounds and the other is a defective Throttle Actuation Control module. The 1997 and 1998 C5 had issues with the TAC modules and there is an up-dated version to replace the old version. You can get them via a Forum vender for $202.00 ( Been there! )

I STRONGLY recommend cleaning your chassis grounds as a start. The grounds are known to cause numerous weird electrical issues that seem to have NO resolve. The dealer will want to throw parts at it until you bleed green!

Here is a link to a post that I started a while back. It will show just about all there is to know about grounds and how to clean them. If you need help, all you need to do is ask.

http://forums.corvetteforum.com/show...al+information

Make sure that you disassemble the ground connectors and clean the pins inside. There is where the real problem is!!

Bill Curlee

 

Wow..great info....that's nasty looking corrosion. Thank you Bill, thats the first thing I am going to do tomorrow. This car was a daily driver and just rolled 70K...it has lots of road grime and sand in all the the little crevices, nooks and crannys, and I can bank money that this has never been checked. I also suspect the TAC module too, as one of the old codes, (in the DIC when I bought it) indicated that. Thanx, Keith

 

If you have ANY questions, PLEASE let me know.

Bill