Can Someone Decipher My Codes
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
Can Someone Decipher My Codes
Hey everyone. On another post I had a problem about my "service engine soon", light. I took off the negative side of the battery for about 5 minutes. When I put back the negative cable it started right up with no light until ten minutes later. So I decided to get the codes by using a paperclip and this is what showed up. First in big letters it said "C12" then underneath it said "1." then 3 bars then "9." then 3 bars then "A." then 3 bars and finally "1.0". Can someone help me with what the codes mean? Thanks in advance, Ed.
Drifting
Joined: Dec 2007
Posts: 1,647
Likes: 4
From: Argillite KY
C12 is a happy code. No problems.
When it said (1 with 3 bars,) that means module1, the CCM module has no problems
When it said 9 with 3 bars that means that module 9 (ABS) has no problems.
When it said "A" with three bars That was an airbag no problem code
The dashes mean that no code is stored.
I'm not sure about the SES light with no codes. Maybe one of these fine folk on here will know about the 96's. I'm an OBD! kinda guy.
When it said (1 with 3 bars,) that means module1, the CCM module has no problems
When it said 9 with 3 bars that means that module 9 (ABS) has no problems.
When it said "A" with three bars That was an airbag no problem code
The dashes mean that no code is stored.
I'm not sure about the SES light with no codes. Maybe one of these fine folk on here will know about the 96's. I'm an OBD! kinda guy.
The CCM will display all module codes (sequentially) in the speedometer read-out area. Module 1 CCM (central control module) is first, followed by module 4 ECM (engine control module) and finishing with module 9 ABS/ASR EBTCM (anti-lock brake system/acceleration slip regulation/electronic brake traction control module) codes. 1990-1991 Corvette CCMs will not display any ABS/ASR or EBTCM codes.
Module numbers 1, 4 or 9 will display directly below the speedo readout area. The codes themselves will be displayed in place of the speedo readout with a prefix: H for History or C for Current, followed by the code. Once all module codes are displayed, “—” displays, ending the sequence. If any codes are missed, turn the ignition off and then back to the on position to restart the code display. There is no limit to this procedure.
Example: H72 code. This may have been caused from someone driving the car with the radio out for service. The code set and was not cleared after repairs were done. If the problem causing the code is fixed, the code must be cleared. The CCM will not display “SYS” if the problem is repaired. However, the code will remain in history until cleared. It’s always best to record all the codes, clear them, and run the engine or operate the system causing the code to see if any codes reoccur.
Once the automatic code read-out sequence is complete, a manual mode is entered. When a manual mode is entered, the speedometer read-out area will be blank. The trip monitor area will display “1.0″, indicating module 1 is ready for manual control using the DIC (Driver Information Center) buttons.
Push the “TRIP/ODO” button a defined number of times to select the system you would like to interrogate:
Once and “1.1″ will be displayed. Fault codes could then be displayed.
Twice 1.2 to display 1.2 (CCM data).
Three times to display 1.3 (CCM inputs/status). This is an interactive display to verify that the CCM is receiving inputs from switches, etc.
Four times to display 1.4. This is also interactive, as it allows you to actuate some of the CCM control circuits.
CCM data, inputs and status will be displayed in the odometer readout area.
Once you find the mode you want to display, press “ENG/MET” to advance to that particular function. Press “FUEL INFO” to go backwards.
Example: to determine if the door pin switches are working properly, start by pushing the “TRIP/ODO” button until reaching mode 1.3. Then, push the “ENG/MET” button until reaching 04 in the 1.3 mode list. If the door is open, “1″ should display in the odometer readout area. When the door is closed, “0″ should then be displayed next to the “1″. Each time the door is opened and closed, the respective numeral will display. “1 0 1″ will display if the door was closed, opened and closed again
Module numbers 1, 4 or 9 will display directly below the speedo readout area. The codes themselves will be displayed in place of the speedo readout with a prefix: H for History or C for Current, followed by the code. Once all module codes are displayed, “—” displays, ending the sequence. If any codes are missed, turn the ignition off and then back to the on position to restart the code display. There is no limit to this procedure.
Example: H72 code. This may have been caused from someone driving the car with the radio out for service. The code set and was not cleared after repairs were done. If the problem causing the code is fixed, the code must be cleared. The CCM will not display “SYS” if the problem is repaired. However, the code will remain in history until cleared. It’s always best to record all the codes, clear them, and run the engine or operate the system causing the code to see if any codes reoccur.
Once the automatic code read-out sequence is complete, a manual mode is entered. When a manual mode is entered, the speedometer read-out area will be blank. The trip monitor area will display “1.0″, indicating module 1 is ready for manual control using the DIC (Driver Information Center) buttons.
Push the “TRIP/ODO” button a defined number of times to select the system you would like to interrogate:
Once and “1.1″ will be displayed. Fault codes could then be displayed.
Twice 1.2 to display 1.2 (CCM data).
Three times to display 1.3 (CCM inputs/status). This is an interactive display to verify that the CCM is receiving inputs from switches, etc.
Four times to display 1.4. This is also interactive, as it allows you to actuate some of the CCM control circuits.
CCM data, inputs and status will be displayed in the odometer readout area.
Once you find the mode you want to display, press “ENG/MET” to advance to that particular function. Press “FUEL INFO” to go backwards.
Example: to determine if the door pin switches are working properly, start by pushing the “TRIP/ODO” button until reaching mode 1.3. Then, push the “ENG/MET” button until reaching 04 in the 1.3 mode list. If the door is open, “1″ should display in the odometer readout area. When the door is closed, “0″ should then be displayed next to the “1″. Each time the door is opened and closed, the respective numeral will display. “1 0 1″ will display if the door was closed, opened and closed again
Last edited by 1963SS; Aug 3, 2011 at 03:46 PM.
Drifting
Joined: Dec 2007
Posts: 1,647
Likes: 4
From: Argillite KY
Oops, I just saw that you have a 1996. MY BAD
That would be an OBD2 and I don't think all the codes will show up by using the shorting technique. I'm not real familiar with the OBD2 Corvettes, but you may need to have Autozone or someone scan it for you. Maybe someone that knows more will chime in.
That would be an OBD2 and I don't think all the codes will show up by using the shorting technique. I'm not real familiar with the OBD2 Corvettes, but you may need to have Autozone or someone scan it for you. Maybe someone that knows more will chime in.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Oops, I just saw that you have a 1996. MY BAD That would be an OBD2 and I don't think all the codes will show up by using the shorting technique. I'm not real familiar with the OBD2 Corvettes, but you may need to have Autozone or someone scan it for you. Maybe someone that knows more will chime in.
That would be an OBD2 and I don't think all the codes will show up by using the shorting technique. I'm not real familiar with the OBD2 Corvettes, but you may need to have Autozone or someone scan it for you. Maybe someone that knows more will chime in.
Any AutoZone store in the Bay Area will retrieve the codes and they should also tell you what they are. Post them up once you get them.
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
Okay, I just went to AutoZone closest to my house, but they don't offer the service of retrieving codes. However, he knew someone that owns a muffler and brake shop who will retrieve codes for free. I went there and he hooked up the code retriever. It said that the problem was with the MAF sensor and he didn't know how much it would cost to fix. Now, is there something I can do or clean without having to pay a mechanic? Any help would be appreciated, Ed.
Drifting
Joined: Dec 2007
Posts: 1,647
Likes: 4
From: Argillite KY
Did he give you a code number like DTC 48 or something else? Make sure that you have 12 volts to the MAF and the black and white wire should be ground. If you have that you may try to clean the wires in the MAF. Be very careful because they will break easily. Autozone sells a cleaner just for the MAF that will leave no residue. Some electrical contact cleaner will work also. I've used a q-tip and the cleaner with success. Try unplugging and resetting the plugs also.
The other wire on the MAF is a wire that sends a frequency to the PCM. If you have access to a meter like the Fluke 87 series they will measure frequency. It is usually around 1100-1300 Hz at idle and goes smoothly up as RPM increases.
The other wire on the MAF is a wire that sends a frequency to the PCM. If you have access to a meter like the Fluke 87 series they will measure frequency. It is usually around 1100-1300 Hz at idle and goes smoothly up as RPM increases.
Last edited by 1963SS; Aug 3, 2011 at 10:29 PM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Could be loose / bad connection or ground wire somewhere.
Requires further investigation before wasting $$$ on a new MAF
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Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
Can I check and/or fix the connection myself it that's the case. Is the connection under the MAF and how could I get to the connection?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
There is a procedure to work through in order to determine the problem.
For a OBD1 LT1 car but should be similar process for yours
http://www.mifbody.com/DTCs/DTC%2048.jpg
http://www.mifbody.com/DTCs/DTC%2048_2.jpg
For a OBD1 LT1 car but should be similar process for yours
http://www.mifbody.com/DTCs/DTC%2048.jpg
http://www.mifbody.com/DTCs/DTC%2048_2.jpg