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

Service ASR light

Old 07-06-2010, 10:26 AM
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wzschirnt
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Default Service ASR light

My 96 started showing "Service ASR" and ASR Off" lights. No 'current' codes, but a CODE 65 showed up in the 'history'.
A friend and I went through the trouble-shooting chart in the Service Manual (pretty confusing!!), traced wires back to the ASR/ABS computer behind driver's seat (continuity, etc); found no problems.

Any ideas on the next step(s)?

Thanks for any help.
walt
Old 07-06-2010, 10:36 AM
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sailorsteve
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Originally Posted by wzschirnt
My 96 started showing "Service ASR" and ASR Off" lights. No 'current' codes, but a CODE 65 showed up in the 'history'.
A friend and I went through the trouble-shooting chart in the Service Manual (pretty confusing!!), traced wires back to the ASR/ABS computer behind driver's seat (continuity, etc); found no problems.

Any ideas on the next step(s)?

Thanks for any help.
walt
Check the brake fluid level in the master cyl.
Old 07-08-2010, 05:11 PM
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wzschirnt
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Fluid level looks wonderful.
Old 07-08-2010, 05:50 PM
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fc_soldier
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If the light is on you have a code. It isnt a OBD2 code so it will come clean there. You need the ABS scanner tool. They have it dealers and local parts stores.



If you got it scanned that way and it still doesnt pop a code. Do you hear any unusual noise? Check the wheel bearing wires, if they get worn or pinched it will trip your ASR.
Old 07-09-2010, 03:28 PM
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No unusual noises when the light came on. I seem to remember that I got on the gas hard (because it felt good!) and the light came on. Wires at the wheels that I can see look good.

I did get a CODE 65 to show up in the code 'history'. I'll get the ABS scanner (been using a Snap-on code reader, but not sure about ABS scanning capabilities).

Thanks.
walt
Old 07-09-2010, 04:04 PM
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sailorsteve
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Originally Posted by wzschirnt
No unusual noises when the light came on. I seem to remember that I got on the gas hard (because it felt good!) and the light came on. Wires at the wheels that I can see look good.

I did get a CODE 65 to show up in the code 'history'. I'll get the ABS scanner (been using a Snap-on code reader, but not sure about ABS scanning capabilities).

Thanks.
walt
Do you have the '96 FSM? According to my '92 FSM the ABS will self-diagnose but your car has OBD II diagnostics. In my manual, Code 65 is called out as "Adjuster Assembly Fault" and from a quick read of this info, you may have triggered the code with your right foot because it is set during an "ASR event". This manual has a detailed but easy-to-follow tree chart that walks you through various circuit checks, etc. I don't know how much of it is directly applicable to your '96, but as with most auto repair, the bulk of the effort and time is in the diagnosis. If your book has this sort of info, it should lead you straight.
Old 07-10-2010, 11:17 AM
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You are correct about the Code 65 being the "Adjuster Assembly Fault". I have the 96 FSM, but I don't know if I agree about the diagnosis tree being "easy to follow". Is this "fault" a mechanical problem - cable slipped inside the ASR unit (it doesn't look like it has moved) or an electrical one? One thing my friend and I noticed was that the voltage at the ASR is different in my 96 than in his 96; mine shows about 2 volts and his shows 12.5. We traced wires back to the ASR/ABS computer and all seems ok (continuity, voltage both at 12+ volts), but the voltage difference seems to be a clue.
I would like to swap the ASR part of the computer with his, but am hesitant about whether separating the computer will result in a lot of brake fluid leakage. Any ideas about that?

Thanks
walt
Old 07-10-2010, 01:34 PM
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If you find it to be a faulty asr unit I do have one. Just letting you know.
Old 07-10-2010, 03:03 PM
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Originally Posted by wzschirnt
You are correct about the Code 65 being the "Adjuster Assembly Fault". I have the 96 FSM, but I don't know if I agree about the diagnosis tree being "easy to follow". Is this "fault" a mechanical problem - cable slipped inside the ASR unit (it doesn't look like it has moved) or an electrical one? One thing my friend and I noticed was that the voltage at the ASR is different in my 96 than in his 96; mine shows about 2 volts and his shows 12.5. We traced wires back to the ASR/ABS computer and all seems ok (continuity, voltage both at 12+ volts), but the voltage difference seems to be a clue.
I would like to swap the ASR part of the computer with his, but am hesitant about whether separating the computer will result in a lot of brake fluid leakage. Any ideas about that?

Thanks
walt
The Code 65 description says, "Code 65 will set if CKT 1685 or CKT 1686 are shorted to ground, shorted to B+, shorted to each other, or both open at the same time. Maybe you could investigate using a DVM.
Old 07-13-2010, 10:33 AM
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Originally Posted by fc_soldier
If you find it to be a faulty asr unit I do have one. Just letting you know.
"ASR unit" - is that the part under the hood or the computer behind the driver seat? If the driver seat unit, did you remove it or was it already out? Trying to figure out if the computer removal is a messy (brake fluid everywhere) affair.

Thanks.
walt
Old 07-13-2010, 11:16 AM
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Originally Posted by wzschirnt
"ASR unit" - is that the part under the hood or the computer behind the driver seat? If the driver seat unit, did you remove it or was it already out? Trying to figure out if the computer removal is a messy (brake fluid everywhere) affair.

Thanks.
walt
Its the part under the hood. Driver side and it says asr on the top plastic. Not sure what your issue is but if its that I got one for ya.
Old 07-13-2010, 05:58 PM
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St. Jude Donor 06-'07

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Read this thread, it may help.

http://forums.corvetteforum.com/c4-t...rvice-asr.html

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