Codes on 85
Thread Starter
Instructor
Joined: Nov 2008
Posts: 170
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From: Odessa Tx
Codes on 85
I am getting these codes: 12 14 23 33 42
The one I am concerned about is code12 It says in the book, Diagnostic mode; no distributor signal to ECM; system PASS.
Does this mean it passes or is it failing somehow and what can be wrong?
In reference to code 23 I think this is the TPS which I have set at .54 volts as the book says.
The major problem that I have with the car is this: It is real good off the start and as the rpms get higher it seems to bogg down and create popping sensation. Not real loud but it feels like backifing. The MAF sensor is not hooked up becuase it doesnt work but I have one on the way. Does anyone know what the problem is?
The one I am concerned about is code12 It says in the book, Diagnostic mode; no distributor signal to ECM; system PASS.
Does this mean it passes or is it failing somehow and what can be wrong?
In reference to code 23 I think this is the TPS which I have set at .54 volts as the book says.
The major problem that I have with the car is this: It is real good off the start and as the rpms get higher it seems to bogg down and create popping sensation. Not real loud but it feels like backifing. The MAF sensor is not hooked up becuase it doesnt work but I have one on the way. Does anyone know what the problem is?
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
What book?
Code 12 is not a trouble code. It signifies the beginning and and end of the test. The codes in between the two code 12's are the trouble codes.
Here is the chart. Scroll down to the bottom.
http://corvettebuyers.com/c4vettes/ecm.htm
Code 12 is not a trouble code. It signifies the beginning and and end of the test. The codes in between the two code 12's are the trouble codes.
Here is the chart. Scroll down to the bottom.
http://corvettebuyers.com/c4vettes/ecm.htm
Pro
Joined: May 2007
Posts: 659
Likes: 5
From: Holden, MO
Cruise-In IX Veteran
I am getting these codes: 12 14 23 33 42
The one I am concerned about is code12 It says in the book, Diagnostic mode; no distributor signal to ECM; system PASS.
Does this mean it passes or is it failing somehow and what can be wrong?
In reference to code 23 I think this is the TPS which I have set at .54 volts as the book says.
The major problem that I have with the car is this: It is real good off the start and as the rpms get higher it seems to bogg down and create popping sensation. Not real loud but it feels like backifing. The MAF sensor is not hooked up becuase it doesnt work but I have one on the way. Does anyone know what the problem is?
The one I am concerned about is code12 It says in the book, Diagnostic mode; no distributor signal to ECM; system PASS.
Does this mean it passes or is it failing somehow and what can be wrong?
In reference to code 23 I think this is the TPS which I have set at .54 volts as the book says.
The major problem that I have with the car is this: It is real good off the start and as the rpms get higher it seems to bogg down and create popping sensation. Not real loud but it feels like backifing. The MAF sensor is not hooked up becuase it doesnt work but I have one on the way. Does anyone know what the problem is?
Code 14 is a bad coolant temp sensor voltage low. Yes there are two coolant sensors. This is the one for the ecm not your gauge (dash readout). This allows for the system to go into closed loop mode once the motor reaches operating temp.
Code 23 is for the MAT (manifold air temp) Voltage low. This tells the ecm of the incoming air temp.
Code 42 Electronic spark timing. Could be intermittent. I would fix the other problems first as this could be a result of other problems.
Hope this helps.
Some one else will chime in with some other ideas.
Mike.
Last edited by captmike13; Jan 11, 2009 at 04:44 PM.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
What brand of code reader did you purchase? The reader you purchased may not support the 85 chip/ecm.
You might try the paper clip method to verify the codes you are getting. Take a paper clip and short A & B, then turn iginition to the ON position (do not start). The "check engine" light should flash once then twice (repeated two more times) this is the beginning of the reading and just tells you it is working. The next set of codes are flashed three times each, then onto the next set of codes.....when all the codes have been shown, it will flash once then twice (code 12) a total of three times.
You might try the paper clip method to verify the codes you are getting. Take a paper clip and short A & B, then turn iginition to the ON position (do not start). The "check engine" light should flash once then twice (repeated two more times) this is the beginning of the reading and just tells you it is working. The next set of codes are flashed three times each, then onto the next set of codes.....when all the codes have been shown, it will flash once then twice (code 12) a total of three times.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Remember the codes are for faults in a whole system , not just the sensor itself.
The ECM has done a system check and found something wrong
Could be bad wiring , loose connector , bad earth.
The CTS especially has a major effect on most ECM functions.
The ECM has done a system check and found something wrong
Could be bad wiring , loose connector , bad earth.
The CTS especially has a major effect on most ECM functions.
Thread Starter
Instructor
Joined: Nov 2008
Posts: 170
Likes: 0
From: Odessa Tx
I have the code reader that is basically a box with a loop that attached a and b on the plug. I replaced the knock sensor and for some reason the only codes I am getting now are 14 and 33.
In reference to the coolant sensor is this the one on the passenger side of the block between the 6 and 8 cylinders? I replaced the one in the front under the throttle body on the intake.
In reference to the coolant sensor is this the one on the passenger side of the block between the 6 and 8 cylinders? I replaced the one in the front under the throttle body on the intake.
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Le Mans Master
Joined: Aug 2000
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From: Australia
Team Owner
Joined: Jan 2003
Posts: 20,320
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From: Summerland B.C. Canada
Find the cause of the code 14, that sensor plays a major part in fuel delivery.
http://members.shaw.ca/corvette86/Code%2014.pdf
http://members.shaw.ca/corvette86/Code%2014.pdf