check engine light
Thread Starter
Advanced
Joined: Apr 2006
Posts: 83
Likes: 0
check engine light
just recently my 85 began showing the check engine light a couple seconds after starting. It has done so every time since, it feels like right before the light comes on the power goes down a notch, like it's not getting optimal power. If anyone knows what I'm talking about let me know, I'm not as knowledgeable as most on here. Car seems to run fine otherwise, but just feels a little off. I want to get it smogged because I'm actually going to sell it.
Last edited by masterprice33; Jan 12, 2007 at 04:10 AM.
Thread Starter
Advanced
Joined: Apr 2006
Posts: 83
Likes: 0
Found the codes
After pulling the codes I came up with codes 24, 42, and 43. The speed sensor code is intermittent and I knew about that problem before, but now I have codes 42 and 43. I looked them up and it seems it has to do with the EST circuit (code 42) or the knock sensor circuit, although on another website it said code 43 was electronic spark control (code 43), so which one is it? The car runs fine but these codes concern me. I'm thinking I will clear the codes and then pull the codes again to see if I still have the same. But ANY advice on this would be VERY VERY helpful, I'm trying to sell the car and it needs to pass emissions!
Last edited by masterprice33; Jan 19, 2007 at 05:53 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Indeed the 43 is knock sensor; it could be an issue with the ESC module; there is an upgrade part # on my site with the story.
I advise to clear the codes to see which ones are current; the 42 could be a remnant from the last time timing was set/checked.
I advise to clear the codes to see which ones are current; the 42 could be a remnant from the last time timing was set/checked.
Team Owner
Joined: Jan 2003
Posts: 20,297
Likes: 240
From: Summerland B.C. Canada
Thread Starter
Advanced
Joined: Apr 2006
Posts: 83
Likes: 0
thank a lot guys, I HAVE AN UPDATE! So I finally was able to reset the codes. I started it up again and check engine light came on right away as it has been the last couple weeks. Scanned the codes and it was only code 42 that came up, so I suppose the code 43 was a remnant, and the code 24 comes up intermittently while driving and the speedometer starts FREAKIN out! So anyway, right now I'm only worried about Code 42, the EST circuit. About 3 months ago I had the whole distributor replaced, and I'm noticing that this problem has to do with the ignition module partially. So would you experts say that this code came about because of the distributor replacement? Perhaps a faulty connection? Please respond ASAP, I'm not a mechanic and I'm wondering whether I should take it back to the place I had my distributor replaced and see if they are liable to fix it for free, or if the timing is off....THANKS EVERYONE!!!
Racer
Joined: May 2006
Posts: 293
Likes: 0
Originally Posted by masterprice33
So would you experts say that this code came about because of the distributor replacement? Perhaps a faulty connection?
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
That was going to be my question too. If the original wiring is there for it, it should be brown and white. Sometimes people actually cut the wire when setting timing instead of just simply disconnecting the connector. 
I don't understand the logic behind that, but it happens.
Thread Starter
Advanced
Joined: Apr 2006
Posts: 83
Likes: 0
to answer AGENT 86's question, I'm actually not sure. what does the EST connector look like? Like I said I'm a rookie at this stuff, I know where the brake booster is, so I should be looking for a brown and white wire somewhere hooking up to something. Maybe if you had a picture of the EST connector it would be helpful for this amateur 
. And again, the code 42 started coming up about a couple of weeks ago. At first, it would happen only once in awhile after I started the car. I'd start it once and it would come on, but then I'd turn it off then start the car again then the check engine light would not come on. But more recently it has happened EVERY time I start it, so I don't know if that helps anyone to diagnose what's goin on. I THINK I notice a slight drop in rpm's right when the check engine light comes on, which is about 2 seconds or so after ignition. and YES, agent 86 gave me the troubleshooting guide but it's too complicated for me to understand and I'm sure I'd have to take it to a good mechanic.
. And again, the code 42 started coming up about a couple of weeks ago. At first, it would happen only once in awhile after I started the car. I'd start it once and it would come on, but then I'd turn it off then start the car again then the check engine light would not come on. But more recently it has happened EVERY time I start it, so I don't know if that helps anyone to diagnose what's goin on. I THINK I notice a slight drop in rpm's right when the check engine light comes on, which is about 2 seconds or so after ignition. and YES, agent 86 gave me the troubleshooting guide but it's too complicated for me to understand and I'm sure I'd have to take it to a good mechanic.
Last edited by masterprice33; Jan 24, 2007 at 03:36 AM.
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
Cruise-In IV Veteran
Cruise-In VI Veteran
Cruise-In VII Veteran
Cruise-In VIII Veteran
For the knock sensor, before you begin throwing money at parts, be sure and check the connector and the plastic nipple the electrode plugs into to see it it's caked with oil, grease, or grime.
This can cause a false reading resulting in the trouble code your ECM is detecting.
The knock sensor is mounted on the engine and is designed to detect the high-frequency vibrations caused by spark detonation. By employing a knock sensor, your Vette's computerized engine-control system allows the engine to operate very near its detonation limit--thereby improving power and efficiency.
If you DO determine one or more of your sensors are faulty, I'd replace it with a an O.E.M. AC/Delco/Delphi unit and not a cheapie brand from AutoZone or Checker's.
That's because the O.E.M. sensors are especially calibrated for your engine's ECM. Other brands may not be as exactly fine-tuned and can actually create the same trouble code you're trying to eliminate.
This can cause a false reading resulting in the trouble code your ECM is detecting.
The knock sensor is mounted on the engine and is designed to detect the high-frequency vibrations caused by spark detonation. By employing a knock sensor, your Vette's computerized engine-control system allows the engine to operate very near its detonation limit--thereby improving power and efficiency.
If you DO determine one or more of your sensors are faulty, I'd replace it with a an O.E.M. AC/Delco/Delphi unit and not a cheapie brand from AutoZone or Checker's.
That's because the O.E.M. sensors are especially calibrated for your engine's ECM. Other brands may not be as exactly fine-tuned and can actually create the same trouble code you're trying to eliminate.
Thread Starter
Advanced
Joined: Apr 2006
Posts: 83
Likes: 0
yeah I don't think I can do that, I'm not experienced with electronics of a car, especially with corvettes, so I don't want to go dickin around with the computer and such. I don't even have the tools anyway.