Its weird i REV my engine in park or nuetral over 2,500 RPM's and the SES comes on and then i put the car in drive and drive for like 5 seconds and it turns off. its really weird. I donthave a code reader so i dont know what the problem is!

Garrett

 

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Miscellaneous
Q: How can I display the error codes from a Service Engine Light?

A: If your car does not have the 12 pin DLC connector, you may not be able to manually "flash" your trouble codes. The language "may be possible" appears to suggest that this method should work with most, if not all, 12 pin DLC equipped cars.

 

That article is just all great and everthing, but has incorrect ALDL terminal designations, an incomplete list of DTCs, and contains some other incomplete or somewhat misleading infromation.

I'd gladly mail you a code reader for free, or for your '89 TPI you can try this:

First, you'll need to acquire a GM OBD I ECM Diagnostic Trouble Code Retrieval Tool (commonly known as a paper clip to TGO members). Form this wire into a ‘U' shape.

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 should be a small rectangular cover over the access hole in the lower dash trim, or at least was when the car was delivered.



Insert a tool as described above (paper clip) into the 'A' and 'B' terminals on the ALDL connector:



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 "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.

 

thanks for all the information, and yeah i would love you to send me a code reader!!! that all seemed kind of complicated though. the weird thing is, the light isnt always on it only comes on when i rev my engine so will have to rev my engine and then check for codes?

 

No. Once the SES light comes on, the code is stored in the ECM until you reset it by unhooking the negative battery cable for ~30 seconds or longer.

 

ohh ok thanks, so should i reset my ecm by disonnecting the negative battery cable?

 

yup. i would reset it (make sure key is OFF) and just drive it without revving it in park/neutral. if it comes on check to see what code it is.