88 chevy 2bbl. no scanner comunication
hooked up verus pro verus via multi-1 to three wire conn. per snap on instructions have no comunication can someone help hi-tech:
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First of all, what is the vehicle doing-??
Second, does the SES light come on with key-On-??
Third, with the key-ON, jumper the ALDL pins A to B and watch the SES light flashes.
It should flash 1 then 1-1, indicating 12, then repeat the 1 with a 1-1 indicating a second 12, then do it a third time. If it keeps repeating the code 12, then that is normal as code 12 indicates the capability of outputting codes and code 12 means "no distributor reference pulses" which would be normal without the engine running.
If it shows a code 12 three times and then transitions to a different SES light flashing sequence count the codes carefully. Each code will flash 3 times and then move to the next code. When it transitions back around to code 12, you now have all the codes stored.
DO NOT disconnect the battery as the ECM memory is "volatile" and the stored codes will be lost.
If you do not get any SES light with the ignition key-ON, check your fuses, particularly the Gauges fuse.
There are diagnostic charts in the service manual regarding the SES light and code capabilities and no communication issues. -
If it is an 88 and only has a 3 pin connector then it may not have a PCM. Is the CEL on? Are you sure it doesn't have a 12 pin ALDL under the dash?
Joe"You don't build a reputation on what you're going to do"
Henry FordComment
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Agreed Joe. That's where I was going. I would be surprised if it didn't have any computer controls. In 1986 and 1987 we saw lots of Canadian Emissions vehicles without ECMs but by 1988 they were few and far between. If he can't get what I described to work, I was going to ask the same thing you did. Does it even HAVE an ECM-??Comment
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I was thinking the same thing. I thought by 88 all the ESC boxes were replaced by PCMs (well...ECMs in those days).
So, after a little digging I see what is going on. The only carbureted 2 barrel carb available in the Chevy line is in the Spectrum, also known as the Isuzu I-Mark. It does have a 3 pin connector. In fact it has 2 of them. One for the ECM and one for the Airbag. Once connected they had a standard GM data list.
If there is a No Communication issue, make sure you have the 12V wire hooked up to the Multi 1 adapter. If that is OK, diagnose a No Communication issue in the normal fashion. I'd recommend breaking out the lab scope to see if the is data on the line.
Joe"You don't build a reputation on what you're going to do"
Henry FordComment
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Up here some of the heavier GVWR and big block engines were a year or two behind but by 1989 they were all the same as US federal emissions.Comment
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