HELP HELP!!
My 98 vette wont dirve, the idle is ruff and the computer is telling me "REDUCE ENGINE SPEED" what does this mean? does anybody know what to do?

 

What codes is your computer showing. I had a tac module and a tps sensor go out and put my car into reduce power mode.

 

Artty

Early 97 and 98 C5's had known TAC module issues. It will cause the car to do what yours is doing. Tere is a TSB that explains the problems and what DTC you will see. My 98 (one of the early ones) had the problem bad!!!! It was so bad I was afraid to drive the car any distance from home.

It was so un-reliable and stranded me so many times that I was ready to burn the sucker.

Here are all the things that I did to bring it back to life:

Replace the TAC module with a 99+ module Approx $230.
Clean the grounds. FREE!!!!!
Replace the old dieing battery. $130. Optima red top

Once The grounds were clean and the TAC module was replaced, she ran like NEW!!

The new battery took care of all the FOB sync and memory loss problems I was also having.

The Throttle Acutation Control ( TAC ) module is a black plastic box located in the passengers fender well on the out side of the PCM:








Read your DTC's

This is the absolute best C5 Diagnostic Trouble Code (DTC) web site!!!

http://www.corvettedoctor.com/Code_Main.html
http://www.corvettedoctor.com/index.html


Go to “technical data base” and then to “Corvette ECM Computer Codes”. Then select your year car. Read the instructions and then scroll down to the "READ MORE" window to view the code definitions.\

Here is another very good site:

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix!!


Write down and post your DTC’s Then clear them ALL!

Sound effects are cool too! 


Then clean your grounds!!!

http://forums.corvetteforum.com/showthread.php?t=896875

BC

 

had the same problem right after installing a callaway honker intake system, was throwing a p1514 code. went on for 2 months until i pulled the honker, cleaned my maf sensor and put the stock air filter assy back on. knock on wood, it hasn't missed a beat yet in the last month.

 

Thank you all for the great advice, I will try everthing you guys recomended. I will keep you posted.
YOU GUYS ARE THE BEST!!!!

 

I'm having the same problems with my 97. The car is actually stuck at my job right now. Getting a new battery at lunch and cleaning the 2 front grounds. Hoping that will get me home. I was wondering though how you got such great pictures of the TAC. Did you remove panels? If so how? I would also like to replace the TAC while at work but I'm afraid of opening a can of worms. When getting TAC from Chevy, should I specify 1999 year for TAC?

 

That is the rolling frame at the Bowling Green Corvette museaum!! You can get some reallgood pics there and also at Corvettes at Carsile>

BC

 

with BC...from his advice previously I replaced my TAC and problem was fixed. Although my reduce engine speed and ABS service light didn't come on often..it still came on so before a trip I replaced the TAC.
Thanks BC for the sound advice as always

 

Thanks for the advice. I cleaned 2 front grounds throughly while at work, bought a new battery (because the volts showed 11 before starting) don't know if that was a waste of $. Car drove great for about 3 minutes on way home from work then ding ding ding...Reduced engine power, service traction sys.-AGAIN. Car wouldn't go over 30 mph. Crawled home. I will replace TAC this weekend and clean other grounds.
I pulled codes and they are:

P1220 H
P1221 H
P1515 H
P1571 H C
C1255 H
C1278 H
B2723H
U1064H

I see the codes for throttle position sensor, could that be a result of bad TAC ?
I also couldn't find a definition for code P1571. This concerns me most since it is current.
Any help would be appreciated. Thanks again!

 

BC... I don't have anything to read the problem codes my car is giving
what do you suggest I do, to find out what code I have?
I am thinking of just replacing TAC. so, when I go purchase this I just ask for a TAC year 99 and up. right? I feel so dumb when it comes to electrical parts

 

Bill already told you how to read the codes ....

go to ... http://www.corvettedoctor.com/Code_Main.html

as he listed and it shows how to read the codes ... all you need is your ignition key to put the car in "RUN" mode ....

Helps if you read what Bill is telling ya .....

 

Black Z06! Thank you! for pointing me to the right direction. like I said I am very dumb when it comes to things like this. I will follow the instructions and get the codes and end this problem once and for all.

once again ALL OF YOU GUYS ARE THE BEST!!!

 

Hi Artty, I understand how you feel but have patience and check the easy things first. Loose or corroded connections - poor grounds - pinched wires - signs of battery leakage etc. Perhaps something you did recently in the engine compartment.I went through the same thing right after I got the car and without this forum and people like Bill Curlee I would have given up! FWIW after my reduced engine power problem and reading how the TAC module was a weak link and no good scan tool at my disposal I purchased a new one from Bob @ Fitchner Chev.Well that didnt work so I borrowed a SnapOn Modis scantool from a freind and found my accellerater pedal was bad.After replacing the pedal no more reduced power problems.After you get your codes wright them down and post them up like the other guy on here and Iam sure the help will come.Another good source for DTC and description is here
http://www.gearchatter.com/viewforum40.php
Good luck with it

 

Do you happen to know where I could purchase one (TAC Module for a '99) for $230? My technician is quoting me $628.34 - which seems way overpriced.

BTW, thanks for the ground/splice pack cleaning instructions! Completed, but still get this problem...thanks much!

 

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