C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

help with 1995 fault codes

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Old Feb 11, 2012 | 03:42 PM
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Default help with 1995 fault codes

so i just rebuilt my motor and had the computer tuned at pcmforless.com. i know they erased the previous codes that were stored into the computer and now starting off fresh. here is the problem...i'm getting H41(1),H13(4),H43(4),H64(9),H72(9). the numbers in ( ) are the little numbers that were listed right below the code on the speedo. can anyone help me with this as far as what to change? and is this going to be anything that would stop me from driving the car to try to get the thing broke in? thanks in advance!!
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Old Feb 11, 2012 | 03:54 PM
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They are history codes. Disconnect the battery for a few minutes and reconnect, then run it a bit and see if they come back.
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Old Feb 11, 2012 | 04:59 PM
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will do and i will report back in about 30 min
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Old Feb 11, 2012 | 06:15 PM
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so i got all the same codes again...i disconnected the battery...drove the car till i got the lights and came home. parked the car and shut it off...got the codes and they had the H in front of them. i would assume that the H is going to be there because the car was shut down and was stored. any thoughts?
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Old Feb 11, 2012 | 06:46 PM
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You have three different modules reporting a problem, (the little numbers). 1 is CCM, 4 is PCM, 9 is ABS. Two of the codes are for loss of serial data communication, 41 and 72. Check wiring very carefully. You will need some way to view live data to proceed, if wiring inspection does not locate the trouble area. Good luck, Bob
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Old Feb 11, 2012 | 09:39 PM
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bob,
you think it is straight wiring...that there might not be a problem with any of the parts??
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Old Feb 11, 2012 | 10:41 PM
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You probably don't have all the ground wires connected.
Verify all of the ground wires are connected at G106 and
G107 as shown in the diagram.

G106 is near the oil temperature sensor.
G107 is a stud from the transmission bellhousing to
the engine block.

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Old Feb 11, 2012 | 11:38 PM
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i think you are on to something there because i have all the ground staps attached on the one stud...is there anyway you can make copies of the other side of the motor and the front...i dont know what book you got that from but i dont have it and im still trying to figure out how the wire harness routed to where it doesnt touch anything it shouldnt. ie headers pulleys and other misc stuff. that was a real big help thanks a lot!!!
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Old Feb 12, 2012 | 12:58 AM
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Originally Posted by bill925
so i just rebuilt my motor and had the computer tuned at pcmforless.com. i know they erased the previous codes that were stored into the computer and now starting off fresh. here is the problem...i'm getting H41(1),H13(4),H43(4),H64(9),H72(9). the numbers in ( ) are the little numbers that were listed right below the code on the speedo. can anyone help me with this as far as what to change? and is this going to be anything that would stop me from driving the car to try to get the thing broke in? thanks in advance!!
41 ccm loss of communication with pcm.

72 Serial data line malfunction. The EBTCM detects three
consecutive serial data line messages that are ignored due to
errors in the transmission. (Could be related to the DTC 41 and 64).

13 Left front oxygen sensor open circuit. Engine is at operating
temp. for more than 2 minutes but oxygen sensor voltage is
steady. PCM will go into open loop.

43 problem with knock sensor circuit.

64 Throttle position signal malfunction.
EBTCM is not receiving reference voltage or a TP
sensor signal from the throttle position sensor.


Pic below is top of engine. Shows G108 top of intake manifold.


Pic below is right hand side of engine.



Pic below shows ground stud on back of transmission. One of the
ground wires appears to be a braided cable.



Pic below shows G109 which you probably never messed with. Goes
to passenger frame rail.


Last edited by Hooked on Vettes; Feb 12, 2012 at 01:17 AM.
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Old Feb 19, 2012 | 03:16 PM
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ok i dont get it...i regrounded everything using the pictures cleared the codes and replaced both o2 sensors for good measures...now the only thing i am getting is the dtc #63: bank 2 rf heated o2 #1 circuit open. ive already replaced the o2 sensors...any thoughts? is it safe to drive so i can start the break in of the motor?
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Old Feb 19, 2012 | 05:44 PM
  #11  
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Originally Posted by bill925
cleared the codes and replaced both o2 sensors for good measures...now the only thing i am getting is the dtc #63: bank 2 rf heated o2 #1 circuit open. ive already replaced the o2 sensors...any thoughts?
Before you were getting DTC 13 Left front oxygen sensor circuit open.

Now you're getting DTC 63 Right front oxygen sensor circuit open.

Are you using an extension harness for the oxygen sensors?

Also re-seat the Gray/Clear colored connector at the PCM. That is
where the PCM receives the oxygen sensor signals.

Verify Fuse #20 15amp Oxygen fuse on the end/side of the instrument
panel is good. Should have 12 volts when ignition On.


Clean the frame ground connection at G109. That's the ground for the heater circuit for the oxygen sensor.



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Old Feb 20, 2012 | 12:23 AM
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i tried the reseat...no luck...now i will try the cleaning the ground and checking the fuse...thanks for the info!!!
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