"SYS" displayed for average MPG
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"SYS" displayed for average MPG
Sometimes when driving and it is eratic "SYS" will be displayed where the average MPG and is displayed. The lady I bought it from said that it was searching for the radio (aftermarket Pioneer installed) and that nobody knows for sure but everyones best guess is the radio. Anyone know for sure or had this problem.
1996, Auto, LT1, Black on Black, with 60000 miles
1996, Auto, LT1, Black on Black, with 60000 miles
Last edited by jrcakc; Aug 16, 2007 at 01:06 PM.
Racer
Joined: Jul 2007
Posts: 281
Likes: 2
From: Mount Vernon Indiana
Sometimes when driving and it is eratic "SYS" will be displayed where the average MPG and is displayed. The lady I bought it from said that it was searching for the radio (aftermarket Pioneer installed) and that nobody knows for sure but everyones best guess is the radio. Anyone know for sure or had this problem.
1996, Auto, LT1, Black on Black, with 60000 miles
1996, Auto, LT1, Black on Black, with 60000 miles
Le Mans Master
Joined: Sep 2003
Posts: 5,874
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From: Littleton CO
Many people will chime in that it is the radio (most likely in your case, as you state it is aftermarket) or a weak battery. Those seem to be the most common, but there are actually lots of other possibilities.
The following is edited from another recent post of mine:
"SYS" indicates that one or more error codes has been set in the CCM/ECM. It may be because of the aftermarket radio, or one of those computer modules has seen a problem with one of the many other functions they control.
To be thorough, check codes as shown here: http://www.corvettebuyers.com/c4vettes/codes.htm
You'll need to scroll to the end to find the correct ALDL pins to jump for '96. If my understanding is correct, any codes that will flash "SYS" can be seen this way, but you must keep in mind that '96 is OBDII and that this method does not access the PCM codes (these set the check engine light) as suggested by that site.
If the aftermarket stereo is indeed the cause (as it is for me), it is because the computer is not seeing the circuit which dims the stock radio display. The associated code, IIRC, is C72.
The following is edited from another recent post of mine:
"SYS" indicates that one or more error codes has been set in the CCM/ECM. It may be because of the aftermarket radio, or one of those computer modules has seen a problem with one of the many other functions they control.
To be thorough, check codes as shown here: http://www.corvettebuyers.com/c4vettes/codes.htm
You'll need to scroll to the end to find the correct ALDL pins to jump for '96. If my understanding is correct, any codes that will flash "SYS" can be seen this way, but you must keep in mind that '96 is OBDII and that this method does not access the PCM codes (these set the check engine light) as suggested by that site.
If the aftermarket stereo is indeed the cause (as it is for me), it is because the computer is not seeing the circuit which dims the stock radio display. The associated code, IIRC, is C72.
Last edited by jrp; Aug 16, 2007 at 02:49 PM.
Le Mans Master
Joined: Sep 2003
Posts: 5,874
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From: Littleton CO
Racer
Joined: Jul 2007
Posts: 281
Likes: 2
From: Mount Vernon Indiana
The TSB link from the site is too blurry to read. It involves adding two 1/2 watt resisters inline with two circuits, but from the linked TSB I can't tell which ones. Fix looks easy enough if you can figure out which circuits to add it to.
