Codes

[bungea]

Has anyone ever used a key that can retrieve codes, the code is suppose to be emitted off the dash. I went to the local autozone place and they said to use this but didn't be specific on how to use it. i have a 95 pontiac bonneville se with a 96 old delta 88 engine. thanks

[Blue Bowtie]

The 1994 and 1995 model years could have been either of two basic control system architectures in GM vehicles.

If your vehicle has the older style ECM and older ALDL connector, you may be able to use a "key" to retrieve error codes.



If the vehicle has the newer style DLC, you probably cannot us a "key" or jumper to retrieve error codes.



If your connector is like the first diagram, you should be able to retrieve codes without a scan tool, using only a "key" or jumper wire, paper clip, guitar string, or whatever else conducts electricity.

First, You’ll need to acquire a GM ECM Diagnostic Trouble Code Retrieval Tool. (Most of us just call them “paper clips, but GM has to have some fancy name for them to charge more.) Cut the clip in half so that one end of it is still bent in a “U” shape. If you’re careful, you can make TWO error code retrieval tools from one paper clip.

With the engine and ignition turned off, locate the ALDL connector under the dash, just to the right of the steering wheel in the driver's foot well area on some models, and on the left on others, depending on the make and year. There may be a small rectangular cover over the access hole in the lower dash trim.



Insert a jumper tool or the aforementioned paper clip into the 'A' and 'B' terminals on the ALDL connector (See diagram above).

WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) - it will begin to flash. This is also commonly called the “Check Engine”, “CEL”, "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

You'll need Adobe Acrobat Reader to open/print the file.

[richtazz]

94-95 GM vehicles that have the 12-pin use a hybrid that doesn't have terminals in the typical A & B positions, so you'll have to have a scan tool with a specific connector to pull codes from these cars. Most DIY scan tools (including those used by A-Z and Advance) cannot pull the codes from these cars.