What the hell is code C12 on module one?
Thread Starter
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
What the hell is code C12 on module one?
This is the CCM, correct? Well the manual starts at DTC13.... 
WTF is up wid dat? 
Oh, it's on my '95 LT1. I have no CCM issues that I know of.
WTF is up wid dat? Oh, it's on my '95 LT1. I have no CCM issues that I know of.
Thread Starter
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by Steel Blue 91
I think you are still running OBDI. If so it's like my L98 and C12 is just a check value. Not too familar with the 95 LT1 so I might be mistaken.
Melting Slicks
Joined: Feb 1999
Posts: 3,261
Likes: 9
From: sonoma ca
C 12 indicates that the diagnostic system is operating & that you have no stored DTC'S in the CCM.
You are OBD I with some OBD II codes that were inserted prior to mandatory compliance to II in 96
for testing purposes.
You are OBD I with some OBD II codes that were inserted prior to mandatory compliance to II in 96
for testing purposes.
Thread Starter
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by aminnich
That's the best code and only one you ever want to see. Relax, have another brew.
Advanced
Joined: Jan 2022
Posts: 73
Likes: 2
From: Pendleton, Oregon
I was reading your reply sounds like you are familiar with the Codes for my 1991 C4 I am having trouble understanding the display. I jotted down a few of the numbers: I hope you can help me understand this please.
Module 1.2
01=174
02=0
03=16
04=599 or 533 hard to tell a 9 from a 3
05=0
06=35 or 95
07=122
08=11.6
09=85
10=71
11=100
12=100
13=148
last parameter had no number assigned -- 3 180 123
Module 1.2
01=174
02=0
03=16
04=599 or 533 hard to tell a 9 from a 3
05=0
06=35 or 95
07=122
08=11.6
09=85
10=71
11=100
12=100
13=148
last parameter had no number assigned -- 3 180 123
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Advanced
Joined: Jan 2022
Posts: 73
Likes: 2
From: Pendleton, Oregon
sorry I am not sure what VATS is exactly -- but I couild not make out the difference between a 3 and a 9 on the digital read out. So it is one of the two. I have to get a younger person to read the screen. I assume 06 is a 35. Do you know what or where to find the a description of the numbers I am seeing?
Advanced
Joined: Jan 2022
Posts: 73
Likes: 2
From: Pendleton, Oregon
thank you so much for the info. Going to those pages now in my FSM. Thanks again. I have been having AC control head issues. AC is fine but it is not controlling when I reset the codes it works using 1.7 and 4.7 weird. I also know I do not have a reference to ground negative battery terminal to the engine so I am going to check my grounding points.
