I purchased a FACTORY SERVICE MANUAL for my corvettes.
simply due to constantly being frustrated at not being able to find,isolate and fix some troubles,
IT is usually rather helpful, but it also pisses me off when it occasionally says
"needs further testing on shop diagnostic computer"
now with the more modern cars I think theres no way you can avoid purchase of a lap top compatible real time diagnostic soft ware program that plugs into the car.
READING CODES (WHAT ARE THE TROUBLE CODES)
The following procedure applies to models with the 12 pin diagnostic connector only.
Turn the ignition switch OFF . Locate the Assembly Line Diagnostic Link (ALDL), usually under the instrument panel. It may be within a plastic cover or housing labeled DIAGNOSTIC CONNECTOR. This link is used to communicate with the ECM.
Use a small jumper wire to connect Terminal B of the ALDL to Terminal A. As the ALDL connector is viewed from the front, Terminal A is on the extreme right of the upper row; Terminal B is second from the right on the upper row.
After the terminals are connected, turn the ignition switch to the ON position but do not start the engine. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence.
After Code 12 has been transmitted 3 times, the fault codes, if any, will each be flashed in the same manner three times. The codes are stored and transmitted in numeric order from lowest to highest.
The order of codes in the memory does not indicate the order of occurrence.
If one or more codes are stored, record them. At the end of the procedure, perform a visual and physical check of each system.
Switch the ignition OFF when finished with code retrieval
do you have a shop manual and a multi meter?
http://garage.grumpysperformance.com/index.php?threads/odbii-scanners.9697/#post-43191
http://garage.grumpysperformance.co...ard-starting-tpi-crossfire-or-lt1-vette.1401/