ABS/ASR Codes
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
ABS/ASR Codes
Driving home today my '93 LT-1 sputtered. A little while later the engine just died. I waited about 5 minutes and I was able to start and drive the one mile home.
The ASR light was on all of the way home.
When I got home, I put the scanner on it and I got the following two ABS/ASR codes:
62 TACH Pulse Fault
72 Serial Data Link
Okay... Now what?
The ASR light was on all of the way home.
When I got home, I put the scanner on it and I got the following two ABS/ASR codes:
62 TACH Pulse Fault
72 Serial Data Link
Okay... Now what?
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
For the 62 code the FSM says, " A short to Ground in CKT 121 with the LT1 (VIN P) engine may cause driveability problems. If the ground is on the ignition system side of the tach filter, there may be a no start or extreme driveability condition.
Well that's me.
My problem now is that I have no idea where CKT 121 is located. The FSM has a nice diagram, but it is unfamiliar nomenclature. Where are "G1" (C100) or "E" (C156) or "R" (C413)?
This may also be a clue. I just rebuilt the entire engine a few months ago. Only 2000 miles on the new engine. It has all new sensors.
Well that's me.
My problem now is that I have no idea where CKT 121 is located. The FSM has a nice diagram, but it is unfamiliar nomenclature. Where are "G1" (C100) or "E" (C156) or "R" (C413)?
This may also be a clue. I just rebuilt the entire engine a few months ago. Only 2000 miles on the new engine. It has all new sensors.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I would start by clearing the codes. How is the car running now, is there any problem. You might have to wait for a re-occurrence of the problem if it is good now. I would still check for codes at least every day just to see if one develops. There could have been a code in there that was not related to your current problem.
I’m not sure if removing the battery cable will clear the brake computer codes on the 93. I know on the 94 I have to do it thru the 9.7 module on the spedo (or use Tech1).
Possibly the Tach filter or coil could be a problem, but lets not jump to fast, there's not much information to go on at this point. Unless you have more in a day or so.
I’m not sure if removing the battery cable will clear the brake computer codes on the 93. I know on the 94 I have to do it thru the 9.7 module on the spedo (or use Tech1).
Possibly the Tach filter or coil could be a problem, but lets not jump to fast, there's not much information to go on at this point. Unless you have more in a day or so.
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
I would start by clearing the codes. How is the car running now, is there any problem. You might have to wait for a re-occurrence of the problem if it is good now. I would still check for codes at least every day just to see if one develops. There could have been a code in there that was not related to your current problem.
I’m not sure if removing the battery cable will clear the brake computer codes on the 93. I know on the 94 I have to do it thru the 9.7 module on the spedo (or use Tech1).
Possibly the Tach filter or coil could be a problem, but lets not jump to fast, there's not much information to go on at this point. Unless you have more in a day or so.
I’m not sure if removing the battery cable will clear the brake computer codes on the 93. I know on the 94 I have to do it thru the 9.7 module on the spedo (or use Tech1).
Possibly the Tach filter or coil could be a problem, but lets not jump to fast, there's not much information to go on at this point. Unless you have more in a day or so.
I can clear the codes. I'm using a MATCO ProScan Plus scanner. However, I would rather replace parts than get stranded.
I'm not all that excited about sitting at the side of the road in a Corvette. It's tacky. A process that is best left to Porches.I have no idea where the "Tach Filter" is located, and I can't check the wiring because I have no idea where these "wires" are located.
It's not that easy to pry information out of the FSM. Right now I'm just reading the entire section on ABS/ASR. My hope is that somewhere the FSM will actually "tell" me where these parts are located.
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
More info.
On the cluster side of the filter the resistance is 6K ohms.
On the Ignition Coil side of the filter the resistance is 30 ohms. Yeah, like almost a dead short.
Could my problem be my brand new fancy MSD coil?
On the cluster side of the filter the resistance is 6K ohms.
On the Ignition Coil side of the filter the resistance is 30 ohms. Yeah, like almost a dead short.
Could my problem be my brand new fancy MSD coil?
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
More information:
With the Ignition Coil "unplugged":
The resistance on the Cluster side of the Tach Filter is 8.93K ohms.
The resitance on the Inigtion side of the Tach Filter is 24.42K ohms.
With the Ignition Coil "plugged" into the circuit:
The resistance on the Cluster side of the Tach Filter is 5.67K ohms.
The resitance on the Inigtion side of the Tach Filter is 4.7ohms.
There is no real short to ground.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
I'm stuck! What caused the car to die? What caused the ABS/ASR 62 & 72 Codes. I can't drive a car that intermittantly dies.
Any ideas?
With the Ignition Coil "unplugged":
The resistance on the Cluster side of the Tach Filter is 8.93K ohms.
The resitance on the Inigtion side of the Tach Filter is 24.42K ohms.
With the Ignition Coil "plugged" into the circuit:
The resistance on the Cluster side of the Tach Filter is 5.67K ohms.
The resitance on the Inigtion side of the Tach Filter is 4.7ohms.
There is no real short to ground.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
I'm stuck! What caused the car to die? What caused the ABS/ASR 62 & 72 Codes. I can't drive a car that intermittantly dies.
Any ideas?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
You might have 2 problems here.
I could be wrong on this but in my notes code 62 is something else, are you sure your right. I show engine oil sensor?
This is all part of the ignition and coil system, not ABS section. In my 94 book it is in several places but the one I have now is page 6E3-C4-4, “Distribution Ignition System”.
It shows all the points you indicated in your post
I have no idea where you are making those resistance readings. For them to be of value, you have to know what is the expected reading. So I can't comment on any of your measurements.
Your ohms law on this is meaningless. The math is right but that is for a steady state DC circuit. But the coil both input and out is AC where its frequency varies with RPM. So forget about figuring the current is more complicated and not necessary.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
What sensors did you replace?
If you have the original coil, I would just hang it and connect it back it and see if it runs.
I could be wrong on this but in my notes code 62 is something else, are you sure your right. I show engine oil sensor?
For the 62 code the FSM says, " A short to Ground in CKT 121 with the LT1 (VIN P) engine may cause driveability problems. If the ground is on the ignition system side of the tach filter, there may be a no start or extreme driveability condition.
Well that's me.
My problem now is that I have no idea where CKT 121 is located. The FSM has a nice diagram, but it is unfamiliar nomenclature. Where are "G1" (C100) or "E" (C156) or "R" (C413)?
This may also be a clue. I just rebuilt the entire engine a few months ago. Only 2000 miles on the new engine. It has all new sensors.
Well that's me.
My problem now is that I have no idea where CKT 121 is located. The FSM has a nice diagram, but it is unfamiliar nomenclature. Where are "G1" (C100) or "E" (C156) or "R" (C413)?
This may also be a clue. I just rebuilt the entire engine a few months ago. Only 2000 miles on the new engine. It has all new sensors.
This is all part of the ignition and coil system, not ABS section. In my 94 book it is in several places but the one I have now is page 6E3-C4-4, “Distribution Ignition System”.
It shows all the points you indicated in your post
More information:
With the Ignition Coil "unplugged":
The resistance on the Cluster side of the Tach Filter is 8.93K ohms.
The resitance on the Inigtion side of the Tach Filter is 24.42K ohms.
With the Ignition Coil "plugged" into the circuit:
The resistance on the Cluster side of the Tach Filter is 5.67K ohms.
The resitance on the Inigtion side of the Tach Filter is 4.7ohms.
There is no real short to ground.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
I'm stuck! What caused the car to die? What caused the ABS/ASR 62 & 72 Codes. I can't drive a car that intermittantly dies.
Any ideas?
With the Ignition Coil "unplugged":
The resistance on the Cluster side of the Tach Filter is 8.93K ohms.
The resitance on the Inigtion side of the Tach Filter is 24.42K ohms.
With the Ignition Coil "plugged" into the circuit:
The resistance on the Cluster side of the Tach Filter is 5.67K ohms.
The resitance on the Inigtion side of the Tach Filter is 4.7ohms.
There is no real short to ground.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
I'm stuck! What caused the car to die? What caused the ABS/ASR 62 & 72 Codes. I can't drive a car that intermittantly dies.
Any ideas?
I have no idea where you are making those resistance readings. For them to be of value, you have to know what is the expected reading. So I can't comment on any of your measurements.
Your ohms law on this is meaningless. The math is right but that is for a steady state DC circuit. But the coil both input and out is AC where its frequency varies with RPM. So forget about figuring the current is more complicated and not necessary.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
What sensors did you replace?
If you have the original coil, I would just hang it and connect it back it and see if it runs.
Thread Starter
Instructor
Joined: Jul 2003
Posts: 217
Likes: 1
From: Atlanta GA
You might have 2 problems here.
I could be wrong on this but in my notes code 62 is something else, are you sure your right. I show engine oil sensor?
The codes are coming from the ABS/ASR. That's what's weird. I believe you are correct that I probably have two problems.
This is all part of the ignition and coil system, not ABS section. In my 94 book it is in several places but the one I have now is page 6E3-C4-4, “Distribution Ignition System”.
It shows all the points you indicated in your post
I have no idea where you are making those resistance readings. For them to be of value, you have to know what is the expected reading. So I can't comment on any of your measurements.
Your ohms law on this is meaningless. The math is right but that is for a steady state DC circuit. But the coil both input and out is AC where its frequency varies with RPM. So forget about figuring the current is more complicated and not necessary.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
What sensors did you replace?
If you have the original coil, I would just hang it and connect it back it and see if it runs.
I could be wrong on this but in my notes code 62 is something else, are you sure your right. I show engine oil sensor?
The codes are coming from the ABS/ASR. That's what's weird. I believe you are correct that I probably have two problems.
This is all part of the ignition and coil system, not ABS section. In my 94 book it is in several places but the one I have now is page 6E3-C4-4, “Distribution Ignition System”.
It shows all the points you indicated in your post
I have no idea where you are making those resistance readings. For them to be of value, you have to know what is the expected reading. So I can't comment on any of your measurements.
Your ohms law on this is meaningless. The math is right but that is for a steady state DC circuit. But the coil both input and out is AC where its frequency varies with RPM. So forget about figuring the current is more complicated and not necessary.
At 12 Volts, 4.7 ohms would draw about 2.7 amps.
What sensors did you replace?
If you have the original coil, I would just hang it and connect it back it and see if it runs.
I'm going to swap the old coil back in tomorrow.
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