sys on dash
Thread Starter
Burning Brakes
Joined: Jul 2000
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sys on dash
I replaced the trans on my 90 ZR-1 this winter. When test driving yesterday I noticed that after filling the gas tank I dont get a range reading. When driving I have no speedo. I have a SYS on the left of the speedo. How do I pull codes to trouble shoot. Any ideas....
Team Owner
Joined: Aug 2004
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From: Park City Utah
I would start by jumping terminals "A and "G" on your ALDL connector under the dash. That will provide you codes for the CCM, ABS, ASR, and some other items.
Since you don't have a SES/CEL light on, that tells me that youre ECM is seeing the VES signal; and you say it's properly pluged into the trans. The SPEEDO gets its display information from the CCM. If you change CCM's, for example, you're odometer reading will change. I would start with pulling codes for the CCM.
-Tom
Since you don't have a SES/CEL light on, that tells me that youre ECM is seeing the VES signal; and you say it's properly pluged into the trans. The SPEEDO gets its display information from the CCM. If you change CCM's, for example, you're odometer reading will change. I would start with pulling codes for the CCM.
-Tom
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Team Owner
Joined: Aug 2004
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From: Park City Utah
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
No worries. Jump A>G then Key on (don't start the engine). Your display should start producing data like this:
You will be looking for the numbers that flash where arrow "1" is pointing (speedo numbers, normally, and also note the numbers shown where arrows "2" and "3" are pointing at for the respective code above.
-Tom
You will be looking for the numbers that flash where arrow "1" is pointing (speedo numbers, normally, and also note the numbers shown where arrows "2" and "3" are pointing at for the respective code above.
-Tom
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St. Jude Donor '12
One other thing to check is your battery charge.
The alternator doesn't put enough juice out to charge it.
Check the codes as well.
The alternator doesn't put enough juice out to charge it.
Check the codes as well.
Heel & Toe
Joined: Mar 2005
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From: Wilmington Ohio
I had a sys error on my 95 LT1 automatic a couple weeks ago when out for first cruise of season. Searched the forum and several users had suggested replacing the battery if questionable. Replaced my 7 year old battery and haven't seen that warning for several hundred miles. By the way, I did let the battery get low over the winter and when I pulled it it had a "black eye" even after being on the charger.
Thread Starter
Burning Brakes
Joined: Jul 2000
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Thanks guys, i didnt have any time to check out to much. Battery was charged all day and was at 12.8v when I started the car.
Noticed the SES light doesnt work when key on engine off. Ill get into the dash Saturday.
Ill get to the codes Saturday morning and get back to you.
Noticed the SES light doesnt work when key on engine off. Ill get into the dash Saturday.
Ill get to the codes Saturday morning and get back to you.
Team Owner
Joined: Aug 2004
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From: Park City Utah
FYI, that isn't true. A properly working alternator puts out plenty of voltage and amperage required to charge and keep the battery, fully charged. That IS the alternators' purpose for existing, and it does it's job.
Race Director
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From: The Top of Utah
Race on!!!
Team Owner
Joined: Aug 2004
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From: Park City Utah
Never heard of such a thing. I believe that it's possible to over work a weak alternator, doing such a task.
But the statement The alternator doesn't put enough juice out to charge it.....that isn't correct. The Alternator does. Maybe to it's detriment, (though I've never seen that happen), but it puts out the volts and amps to charge a battery, given time.
Either way, The OP doesn't have a stone dead battery. Or a dead battery at all. The alternator, if working will certainly keep a decent or even marginal battery, UP. Agreed?
But the statement The alternator doesn't put enough juice out to charge it.....that isn't correct. The Alternator does. Maybe to it's detriment, (though I've never seen that happen), but it puts out the volts and amps to charge a battery, given time.
Either way, The OP doesn't have a stone dead battery. Or a dead battery at all. The alternator, if working will certainly keep a decent or even marginal battery, UP. Agreed?
Team Owner
Joined: Aug 2004
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From: Park City Utah
O.K. "C" means Current and "H" means History. So you have a stored 41 DTC, and an active one. The problem is ongoing.
C41 is "Loss of ECM Serial Data Communications".
That basically means that the ECM and the CCM aren't talking w/each other. The CCM is the "master" in the car, and the other computers are "slaves".
The CCM, ECM, EBCM, ASR, SRS, and I believe the HVAC (if you have the C60 climate control) are all connected by common wires for serial communication. The wires are (or are in my '92) tan. There are two sets; a primary and a secondary (back up). You need to check the connections at the ECM for cleanliness and good contact, and at the CCM too. Then test for continuity from point to point. Then shorts to ground, then shorts to power. If all checks out, I think the ECM is faulty or the CCM is. The service documentation that I have doesn't specify which it could be, or how to determine.
I would start by simply checking the connections at the ECM, since that's so easy. I'll post more shorty, and in the mean time, can you answer this; does the Cruise Control work?...
C41 is "Loss of ECM Serial Data Communications".
That basically means that the ECM and the CCM aren't talking w/each other. The CCM is the "master" in the car, and the other computers are "slaves".
The CCM, ECM, EBCM, ASR, SRS, and I believe the HVAC (if you have the C60 climate control) are all connected by common wires for serial communication. The wires are (or are in my '92) tan. There are two sets; a primary and a secondary (back up). You need to check the connections at the ECM for cleanliness and good contact, and at the CCM too. Then test for continuity from point to point. Then shorts to ground, then shorts to power. If all checks out, I think the ECM is faulty or the CCM is. The service documentation that I have doesn't specify which it could be, or how to determine.
I would start by simply checking the connections at the ECM, since that's so easy. I'll post more shorty, and in the mean time, can you answer this; does the Cruise Control work?...
Last edited by Tom400CFI; Apr 17, 2010 at 12:02 AM.