Affordable full scan tool for the V6 Fieros (Page 4/4)
Romsk JUN 08, 04:18 PM
Thanks 87 and 88 are DIS

Yes, I use IL4 for In Line 4 rather than L4 for Line 4.

If it were a MOPAR, it could have been a S6 (Slant 6).
richard in nc JUN 08, 05:54 PM

quote
Originally posted by Romsk:

Richard,

None of Fiero ECMs that use 160 baud can have their Error Codes (ECs) cleared via the ALDL because the protocol does not receive commands, it only spits out data. The only way to clear ECs in those ECMs is to remove 12V power to the ECM for at least 1 minute. Removing the ECM Fuse will not do this, it has to be power to the ECM that comes from the ECM Fusable Link.

There are two normal ways to do this:
1. Disconnect the Negative side of the Battery for 1 minute (radio settings will be lost).
2. If there is a single wire connector on the ECM Fusable Link (near the battery) disconnect it for 1 minute (radio settings not effected).

The 1988 IL4 ECMs use 8192 baud and I am told they do receive commands. But I do not know if there is a command to erase ECs on that ECM.
I am expanding my GUI to support 4 cylinder Fieros, but I haven't gotten to that ECM yet, so it is a big unknown to me.

You have a 1987 IL4 Fiero, it's 160 baud, no command to clear ECs.

Paul



i did end up unhooking the battery.the cars a 87.the check engine light was on sometimes.i tried to read the codes but came up with 'no codes found'.so i swapped in a 1988 computer i had and was able to read the codes.
1985 Fiero GT JUN 08, 06:01 PM

quote
Originally posted by Romsk:

Thanks 87 and 88 are DIS

Yes, I use IL4 for In Line 4 rather than L4 for Line 4.

If it were a MOPAR, it could have been a S6 (Slant 6).



L4 is for longitudinal 4, as in all cylinders are arranged in a single line.
Romsk JUN 08, 08:30 PM
Thanks, L4 is Longitudinal 4. I will add that to my glossary in the GUI.

But I like In-Line 4 better.
Romsk JUN 08, 08:34 PM
Oooops 1987 and 1988 4 Cylinder were both 8192 Baud. My bad.

How did you read error codes?

DMDIAG Mode and count flashes, or
Send command/responses for Error Codes.
reinhart JUN 14, 10:29 PM

quote
Originally posted by Romsk:

I don't know much about the parallel port cables. I think they are very similar to the serial port cables except they put the data on one of the data pins (possibly D0).
There are small Adapters that you can plug in (or hard wire) to a serial cable to convert it to USB. When I converted my first serial cable I made, I just wired a Parallax Serial/USB adapter to it. There are many sources of these. The Parallax one is:
Parallax USB-Serial Adapter




Thank you that was basically my question. So I need a special controller like what you linked to and can't just use a serial to usb cable like I would use to hook up an old serial cable mouse to a USB port?

Regarding error code clearing, which someone else mentioned, I thought it would be kind of useful to hook up a switch in the cabin that would remove power from the ECM to clear the codes without having to go back to the battery junction area. Should be rather easy..just need to find the wire that goes back to the disconnect back there and splice in by the ECM as well and put a switch in.
Dennis LaGrua JUN 24, 01:05 PM

quote
Originally posted by reinhart:


Thank you that was basically my question. So I need a special controller like what you linked to and can't just use a serial to usb cable like I would use to hook up an old serial cable mouse to a USB port?

Regarding error code clearing, which someone else mentioned, I thought it would be kind of useful to hook up a switch in the cabin that would remove power from the ECM to clear the codes without having to go back to the battery junction area. Should be rather easy..just need to find the wire that goes back to the disconnect back there and splice in by the ECM as well and put a switch in.


The only thing about cutting power to erase codes is that it wipes out the computer memory on how it has adjusted to your driving. On the Fieros that I have owned it takes about 30 minutes of mixed driving to reset the ECM/ or PCM . On the early 84 four cylinder ECM's that might be the exception But I do not own an 84 to confirm.

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[This message has been edited by Dennis LaGrua (edited 06-24-2025).]