My grandfather's 82 keeps throwing out code 43...replaced knock sensor over the weekend and still getting the code. Should I replace the esc module also and where might it be located? I know where they are on later model TPI cars, but can't seem to find it on his. Any help or suggestions would be greatly appreciated.

Thanks in advance.

KC

 

The ESC should be inside the distributor. You could have a computer problem also. I have just seen this same type problem on two 90 models, both were bad computers.

 

I am sorry I can't tell you what the problem is, however I can lead you in the right direction. Get the Corvette Shop Manual. If you have a 82 it is the best tool you can have. Ecklers has a part # A1079 for the 82 and it list for $99.00. This manual is expensive but it has so much info it is invaluable.
Good Luck
Steve

 

You might be thinking of the ignition module, which has been replaced. It could very well be the computer, we are trying to get a good one, been through 3 remans and they all have had different problems. One worked fine for a day or two and then started doing stange things. The one that is in it now seems to be working, but I haven't put my scanner on it yet. I've tried the 747 swap but can't seem to get the chip right (dtc 51 and flashing ses light).

Thank you

KC

 

There are 2 electonic parts in there. Which one did you replace? One is sort of "C" shaped ...not the one with the capacitor. Did you use the heat gel on the bottom of the when you replaced it?

The ESC module Is behind the seats on the metal frame under the carpet or under the arm rest of the consol...picture is kind of fuzzy...should be a blue, black, pink/black, another black and a brown wire going to it.

Shop manual shows an several easy tests. Idle the car at normal temperature. Use a volt meter and probe pin 4 on the white connector at the ECM. Over 6 volts its a faulty ECM or connector to the ECM. Try cleaning them up.

If its less then 6 volts while the car is idling turn the car off.Check pin 4 with the IGNITION ON but engine not running. Over 6 volts it says to check and repair CKT 454 on the sensor shield...thats the black ground on the ESC...basically your ESC module is not grounded. if circuit 454 is good its probably a faulty contoller or knock sensor. If its over 6 volts with the car off but ignition on it says to check voltage at pin4 which is circuit 485 (marked spark retard control) at the ECM...if again you get over 6 volts is a bad ECM. So you basically have tested for over 6 volts at the ECM with the car on and off and it looks like over 6 volts means bad ECM.

Now if the voltage is less the 6 with the igniton on and engine off. It says to proceed to another test.It says to check Pin "J" on the ESC connector with a volt meter to ground...over 6 volts suggests an open signal in circuit 485 between ESC and ECM basically the black wire.

Reading between the lines...best case scenario is one of the two black wires at the ESC are the problem.

Jim

 

The computer is located in the battery compartment behind the drivers seat. It's mounted to the front wall of the compartment.

 

The ESC is mounted on the back of the ECM bracket, it's sandwitched between the ECM and the rear firewall (behind seat)

 

thanks for all the info...I will try the few tests "jdp6000" suggested and see what I come up with. We replaced the module in the dist. and used all of the grease with it, so it shouldn't get hot. The only other electronic part in the dist. was the stator or pickup, whatever you want to call it. I found a test for that last night also.

KC

 

if you get a code 43 you can fiddle with the EST (the module) all night long, you're not gonna fix it.
The problem IS the ESC, the box on the back of the ECM:


It has a 10 pin connector, let's call them pin A B C D E F G H J K
A = ESC sensor shield ground (the outer shield of the thick coaxial cable), a bare metal wire
B = blue (inside wire of coaxial cable), ESC sensor inut
C = not used
D = not used
E = not used
F = 12V ign switched power (also powers ECM from same feed) a pink/black wire
G = not used
H = not used
J = spark retard signal (to ECM) black wire
K = ESC ground (engine ground)

Code 43 is set when the voltage on the black wire (ESC signal to ECM) drops for more than 5 secs w/ engine running
It's also set when the self test/function test fails, a test carried out automatically by the ECM on each stertup.
The test is done at near WOT w/ engine temp close to 200F, the ECM advances the timing to deliberately cause detonation, if none is detected the test is failed and the code is tripped.

This means that if it's not the wiring (check for 12V and proper ground and the black wire to ECM) it's either the sensor or the ESC itself. The sensor is easily checked, it's in the pass side coolant drain, in the bottom of the block. The stock 82 has a push lock type connector that is self locking when you push the metal tab and slide the hole in the rubber block (exposed by pushing the tab) over the little stem on the sensor. Sometimes they fall off.

 

Well, I just got the time to check it all out and with the engine running, the white pin 4 has full voltage, roughly 13.5, definetely more than 6. The grounds to the ESC are all fine and It's getting 12+. So, according to the tests it looks as if we have gotten another bad ecm, which will make 3 in a row.

Thanks again for all the info.

KC

 

Just to let everyone know , it is fixed finally...I put in a supposedly new esc from Zip products (they said it was new on the phone but I think it was a reman, couldn't beat the $40 price though), started it up and haven't seen the SES light yet. Idles like it should and runs alot better.

Thanks for all the help and suggestions...
KC