ESC please confirm for me...
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Racer
Joined: Jun 2005
Posts: 416
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From: Gansevoort NY
ESC please confirm for me...
I had a code 43 rear its ugly head 
and the first thing I did was to check the voltage from the ESC I used connection c and d on the ESC connector while the ignition was on without engine running the value I got was 9.16. So this means bad ESC correct?
and the first thing I did was to check the voltage from the ESC I used connection c and d on the ESC connector while the ignition was on without engine running the value I got was 9.16. So this means bad ESC correct?
Race Director
Joined: Sep 2000
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From: The Top of Utah
Not according to my manual. Code 43 will set when the voltage at "C" is low for longer than 4 seconds. The voltage at "C" should only drop when the ESC is receiving knock signals. Otherwise the voltage should remain above 6 volts. Terminal "D" is simply a ground. Depending on whether the harness was connected to the ESC and the placement of the test probes, "C" and "D" could read the same. If you mean that the probes were on "C" and "D" at the same time, then with "D" being a ground the reading was the voltage at "C" and is well within spec.
RACE ON!!!
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Check YOUR manual to make sure the '84 and the '85 aren't different. I believe they are the same.
PS. As I reread the text and look at the trouble shooting chart, I see that they don't agree. Check your manual very carefully.
RACE ON!!!
PS. As I reread the text and look at the trouble shooting chart, I see that they don't agree. Check your manual very carefully.
RACE ON!!!
Melting Slicks
Joined: Jun 2004
Posts: 3,032
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It's worded oddly in my Helms, in one line it says that the system "sets a Code 43 when the ESC voltage drops below 4 volts at the white #4 connector to the ECM"... but then it says:
the system...
"Checks for intermittant ESC operation. If the voltage is now over 6 volts, it is a faulty ESC terminal C connection at the ESC module."
Could you possibly find another ESC module to try out? Even if it's just for troubleshooting.
If you do change out the ESC, it might be a good idea to get the upgraded ESC model- it's more efficient in recognizing false knock.
Anyway- those are my ideas, but I don't fully understand the system yet.
EDIT::: forgot to mention, that was from an '85 helms.
the system...
"Checks for intermittant ESC operation. If the voltage is now over 6 volts, it is a faulty ESC terminal C connection at the ESC module."
Could you possibly find another ESC module to try out? Even if it's just for troubleshooting.
If you do change out the ESC, it might be a good idea to get the upgraded ESC model- it's more efficient in recognizing false knock.
Anyway- those are my ideas, but I don't fully understand the system yet.
EDIT::: forgot to mention, that was from an '85 helms.
Last edited by mikey whipreck; Sep 15, 2005 at 05:21 PM.
Thread Starter
Racer
Joined: Jun 2005
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From: Gansevoort NY
Well here is what I have done since. Dropped a 8mm socket down the right front lower panel. 
My 5 yearold son has hidden my magnet tool grabber 
. Anyways I reset the codes and I am going to see what conditional driving the error occured during. I ran the car back up to temp and the code wasnt set again. So I'll keep digging. I verified the voltage at the ESC but not the other side at the ECM yet. At any rate there still is some question to exactly what the reference signal is supposed to be. I dont have another ESC but I have a neighbor who is also a forum member UPSTATE who has an 88 that I might be able to test with if it reoccurs.
My 5 yearold son has hidden my magnet tool grabber . Anyways I reset the codes and I am going to see what conditional driving the error occured during. I ran the car back up to temp and the code wasnt set again. So I'll keep digging. I verified the voltage at the ESC but not the other side at the ECM yet. At any rate there still is some question to exactly what the reference signal is supposed to be. I dont have another ESC but I have a neighbor who is also a forum member UPSTATE who has an 88 that I might be able to test with if it reoccurs.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Originally Posted by CFI-EFI
Not according to my manual. Code 43 will set when the voltage at "C" is low for longer than 4 seconds. The voltage at "C" should only drop when the ESC is receiving knock signals. Otherwise the voltage should remain above 6 volts. Terminal "D" is simply a ground. Depending on whether the harness was connected to the ESC and the placement of the test probes, "C" and "D" could read the same. If you mean that the probes were on "C" and "D" at the same time, then with "D" being a ground the reading was the voltage at "C" and is well within spec.
RACE ON!!!
RACE ON!!!
Here's what I have on this. Check the voltage on terminal B7 at the ECM, maybe you have an open circuit:
CODE 43, ELECTRONIC SPARK CONTROL (5.0L & 5.7L)
Code 43 will set if: ECM has seen low voltage at CKT 485,
terminal "B7" in the ECM A-B connector, for more than 6 seconds with
the engine running.
1) Checks to see if ECM recognizes a problem in CKT 485.
2) This will determine if the system is functioning at this
time. The knock sensor should respond if exhaust manifold is tapped
above sensor.
3) ESC module supplies voltage to the ECM. Voltage should
always be above 6 volts unless system is sensing engine detonation.
4) Checks for intermittent ESC operation. If the voltage is
now over 6 volts, it is a faulty ESC terminal "C" connection or ESC
module.
5) Checks for grounded ECM.
6) Checks for open ignition circuit.
Safety Car
Joined: May 2003
Posts: 3,789
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From: [Quote=WOEII] Is dried brown doodie powders man! [/Quote]
Sure, drag me into it 
If the p/n's are the same for the 88 and the 85 just drive on over and we'll swap em out. I have my doubts they are the same but can't back that up with anything. Just my skeptic nature. I know the ECM's are different but what difference that would make for the ESC module I don't know.
If the p/n is printed on the ESC I'll post it when I get home tonight. If they're the same part I'll pull it out and try to get it to you. Our schedules are so different that it's hard to coordinate anything that requires meeting up unless it's Sunday. I'll be home tomorrow morning and awake bright and ugly if you want to stop by, or I can pull the part and leave it in my mailbox and you can pick it up on your way home from work tonight so you'll have it first thing to use Saturday morning. I doubt I'll be awake
I won't be driving the car this weekend, in fact I'll probably start pulling the rear apart for the bearings and u-joints so you won't be putting me out any. Let me know
If the p/n's are the same for the 88 and the 85 just drive on over and we'll swap em out. I have my doubts they are the same but can't back that up with anything. Just my skeptic nature. I know the ECM's are different but what difference that would make for the ESC module I don't know.
If the p/n is printed on the ESC I'll post it when I get home tonight. If they're the same part I'll pull it out and try to get it to you. Our schedules are so different that it's hard to coordinate anything that requires meeting up unless it's Sunday. I'll be home tomorrow morning and awake bright and ugly if you want to stop by, or I can pull the part and leave it in my mailbox and you can pick it up on your way home from work tonight so you'll have it first thing to use Saturday morning. I doubt I'll be awake
I won't be driving the car this weekend, in fact I'll probably start pulling the rear apart for the bearings and u-joints so you won't be putting me out any. Let me know
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Thread Starter
Racer
Joined: Jun 2005
Posts: 416
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From: Gansevoort NY
Originally Posted by Upstate
Sure, drag me into it
If the p/n's are the same for the 88 and the 85 just drive on over and we'll swap em out. I have my doubts they are the same but can't back that up with anything. Just my skeptic nature. I know the ECM's are different but what difference that would make for the ESC module I don't know.
If the p/n is printed on the ESC I'll post it when I get home tonight. If they're the same part I'll pull it out and try to get it to you. Our schedules are so different that it's hard to coordinate anything that requires meeting up unless it's Sunday. I'll be home tomorrow morning and awake bright and ugly if you want to stop by, or I can pull the part and leave it in my mailbox and you can pick it up on your way home from work tonight so you'll have it first thing to use Saturday morning. I doubt I'll be awake
I won't be driving the car this weekend, in fact I'll probably start pulling the rear apart for the bearings and u-joints so you won't be putting me out any. Let me know
If the p/n's are the same for the 88 and the 85 just drive on over and we'll swap em out. I have my doubts they are the same but can't back that up with anything. Just my skeptic nature. I know the ECM's are different but what difference that would make for the ESC module I don't know.
If the p/n is printed on the ESC I'll post it when I get home tonight. If they're the same part I'll pull it out and try to get it to you. Our schedules are so different that it's hard to coordinate anything that requires meeting up unless it's Sunday. I'll be home tomorrow morning and awake bright and ugly if you want to stop by, or I can pull the part and leave it in my mailbox and you can pick it up on your way home from work tonight so you'll have it first thing to use Saturday morning. I doubt I'll be awake
I won't be driving the car this weekend, in fact I'll probably start pulling the rear apart for the bearings and u-joints so you won't be putting me out any. Let me know
I'll get in touch with you this weekend and LYK. Saturday morning my 5 yearold has a soccer game at 8:15 so saturday is out. I'll be in touch though.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
According to my Corvette parts book, the ESC for 1984 - 1986 is a 16022621. For 1987 - 1989, it's a 16052401. That is as late as my book goes. That 1987 - 1989 part number looks like the later, less sensitive ESC that is used in the tech tip. Therefore, it will successfully sub for the 1985 stocker.
RACE ON!!!
RACE ON!!!
Safety Car
Joined: May 2003
Posts: 3,789
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From: [Quote=WOEII] Is dried brown doodie powders man! [/Quote]
Remember when I told you via PM my car was running like crap? Pulled the codes again and in addition to 15, I got a 42 today.
Major Whiskey Tango Foxtrot.
I am going out to follow the procedure in the FSM but I don't have a test light which is a required tool to follow the chart in addition to the DVM. So I am going to see what I can come up with. This sucks.
Anyone have any experience with chasing down this code? I'd rather it be a fried ignition module than to have to chase a bunch of wires
Thread Starter
Racer
Joined: Jun 2005
Posts: 416
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From: Gansevoort NY
Originally Posted by Upstate
Remember when I told you via PM my car was running like crap? Pulled the codes again and in addition to 15, I got a 42 today.
Major Whiskey Tango Foxtrot.
I am going out to follow the procedure in the FSM but I don't have a test light which is a required tool to follow the chart in addition to the DVM. So I am going to see what I can come up with. This sucks.
Anyone have any experience with chasing down this code? I'd rather it be a fried ignition module than to have to chase a bunch of wires
Ouch!!! Do you have a DVM? I have one if you need it. I ran mine pretty hard to work and no 43 waqs set again. I just got done changing my plugs and let me say I dont know how this thing ever ran the way the plugs were gapped. Idle has smoothed out alot as well. Still get the surge every once and awhile but not as often. My 43 so far hasnt come back. I'll be around tomorrow if you need the DVM. What test light are they referring to in the FSM?For which code? 42 isnt that knock sensor?
