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Discussion Starter · #1 ·
Was driving back from AZ to CA last night, and when I stopped at the Texaco right before Blythe on the 10, I couldn't start the car. I couldn't get it to turn over at all. Long story short the check engine light was on and I played around with different things and got it started but it got me thinking. The check engine light triggered and unlike my 4Runner there's no way to know what is wrong without a scan tool. Granted I know the computer in this thing is SUPER primitive but it still tells me something.

So now to the question of this thread; what is the name of the type of scanner the 1984 uses, and where can I get it?
 

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you can scan for codes by shorting the A &B terminals of the dlc.

The actron CP9185 will scan your car if y7ou have the correct adapter.

The Snap On MT2500 will scan your car with the correct cartridge and adapter. They are available on ebay.
 

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I did a thorough study of the Actron CP9185 while I had it and tested it on an 86 Camaro 5.0L carbed pcm. It may give you an idea of the coverage for your 2.8L car, but I can't say for sure. These screens show what is available for the 86 5.0L in addition to reading the trouble codes.

Here is the detail of the data available from the ecm of the 2.8L and I would suspect it is all displayed on the CP9185 (again, not sure)

DATA STREAM:
ENGINEERING
WORD DESCRIPTION CONVERSION UNIT
----
1 PROMID BYTE 1 NONE
2 PROMID BYTE 2 NONE
3 BATTERY VOLTAGE EU = N*.1 VOLTS
4 COOLANT TEMPERATURE TABLE LOOKUP
5 VEHICLE SPEED NONE
6 MANIFOLD ABSOLUTE PRESSURE EU = N * .0196 VOLTS
7 OLDPA3 NONE
8 THROTTLE POSITION SENSOR EU = N*(.0196) VOLTS
9 OXYGEN SENSOR EU = N*4.44 MILLIVOLTS
10 MC SOLENOID EU = N/2.56 % DUTY CYCLE EU = N*60/256
11 MALFUNCTION FLAG WORD 1 NONE
12 MALFUNCTION FLAG WORD 2 NONE
13 MALFUNCTION FLAG WORD 3 NONE
14 CLCC MODE WORD NONE
15 I/O STATUS WORD 1 NONE
16 I/O STATUS WORD 2 NONE
17 EGR DUTY CYCLE EU = N/2.56 % DUTY CYCLE
18 ENGINE RPM EU = N*25 RPM
19 BAROMETRIC PRESSURE EU = N * .0196 VOLTS
20 ALDL RICH LEAN CHANGE COUNTER SEE **
 

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Discussion Starter · #4 ·
I did a thorough study of the Actron CP9185 while I had it and tested it on an 86 Camaro 5.0L carbed pcm. It may give you an idea of the coverage for your 2.8L car, but I can't say for sure. These screens show what is available for the 86 5.0L in addition to reading the trouble codes.

Here is the detail of the data available from the ecm of the 2.8L and I would suspect it is all displayed on the CP9185 (again, not sure)

DATA STREAM:
ENGINEERING
WORD DESCRIPTION CONVERSION UNIT
----
1 PROMID BYTE 1 NONE
2 PROMID BYTE 2 NONE
3 BATTERY VOLTAGE EU = N*.1 VOLTS
4 COOLANT TEMPERATURE TABLE LOOKUP
5 VEHICLE SPEED NONE
6 MANIFOLD ABSOLUTE PRESSURE EU = N * .0196 VOLTS
7 OLDPA3 NONE
8 THROTTLE POSITION SENSOR EU = N*(.0196) VOLTS
9 OXYGEN SENSOR EU = N*4.44 MILLIVOLTS
10 MC SOLENOID EU = N/2.56 % DUTY CYCLE EU = N*60/256
11 MALFUNCTION FLAG WORD 1 NONE
12 MALFUNCTION FLAG WORD 2 NONE
13 MALFUNCTION FLAG WORD 3 NONE
14 CLCC MODE WORD NONE
15 I/O STATUS WORD 1 NONE
16 I/O STATUS WORD 2 NONE
17 EGR DUTY CYCLE EU = N/2.56 % DUTY CYCLE
18 ENGINE RPM EU = N*25 RPM
19 BAROMETRIC PRESSURE EU = N * .0196 VOLTS
20 ALDL RICH LEAN CHANGE COUNTER SEE **
Wait, so are all those different codes that can come back?

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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They aren't trouble codes. The scanner is reading 20 sensors and ECM parameters, and telling you the status of each.

As Gary explains, it will also read the trouble codes (DTC's). The display showing "041" is an example of a DTC. But as Robert already mentioned, you don't need a scanner to pull the codes. All you need is a paper clip to short the ALDL pins, and flash the codes on the check engine light.
 
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Discussion Starter · #6 ·
They aren't trouble codes. The scanner is reading 20 sensors and ECM parameters, and telling you the status of each.

As Gary explains, it will also read the trouble codes (DTC's). The display showing "041" is an example of a DTC. But as Robert already mentioned, you don't need a scanner to pull the codes. All you need is a paper clip to short the ALDL pins, and flash the codes on the check engine light.
I know about the shorting trick, I just would prefer a more concrete method. It never worked well on my 4runner.

And I when I saw that list say throttle body and oxygen sensor and all that I just assumed of was a list of codes. It's nice to have a list of what the codes mean handy. Makes life easier

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GM and toyota do not retrieve codes the same way. Pre 94 GM cars all can get codes by shorting Dlc pins.

Your 84 is pretty primitive in the car computer world. The amount of data available on a running sensor scan is very limited.

By 90 when my 3rd gen was built, more data was available on a running sensor scan. Because of the multiport fuel injection used.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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....... It's nice to have a list of what the codes mean handy. Makes life easier

Sent from my iPhone using Tapatalk
The code list descriptions in the scanner database are often "generic" and can be misleading. Gary has found a fairly expensive scanner made by Innova that has a totally corrupt list of scanner codes for the OBD-1 LT1 engines use in our 4th Gens, even showing codes that don't exist.. You need a list specifically for the model/year/engine of the vehicle you are scanning to be confident in the results.
 

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Discussion Starter · #9 ·
GM and toyota do not retrieve codes the same way. Pre 94 GM cars all can get codes by shorting Dlc pins.

Your 84 is pretty primitive in the car computer world. The amount of data available on a running sensor scan is very limited.

By 90 when my 3rd gen was built, more data was available on a running sensor scan. Because of the multiport fuel injection used.
Actually from what I've researched they're pretty similar. You short a couple ports, the check engine light flashes telling you the code and you go look it up. Maybe the computer systems are different but its the same process.

And yeah I know the computers are primitive. I used to say that my 4runner would only warn me right before the engine blew up and it didn't even do that and its a 90. Can't imagine the 84 is any better.
The code list descriptions in the scanner database are often "generic" and can be misleading. Gary has found a fairly expensive scanner made by Innova that has a totally corrupt list of scanner codes for the OBD-1 LT1 engines use in our 4th Gens, even showing codes that don't exist.. You need a list specifically for the model/year/engine of the vehicle you are scanning to be confident in the results.
Yeah codes are extremely generic. My 4runner had a AFM code stored in the system (doesn't trip the check engine light though for some reason) and I've cleaned the crap out of it and it still doesn't go away. I just decided to give up on that code and work on other things.

But yeah I have a whole list of 90 4Runner codes written somewhere. Want to do the same with the Firebird.

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Your best bet to get an accurate list of codes is to find the 84 factory service manual . It will have all the codes listed, what they mean, what causes them to set. Also troubleshooting help.
 
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