OBD II Trouble Code P0700 indicates your 1996 Chevy Silverado's engine computer has noticed that the transmission computer has a fault. This causes the PCM (engine computer) to turn the Malfunction Indicator Lamp on (in most cases).
Your Silverado has a control module for the automatic transmission called a transmission control module (TCM). When the TCM detects a transmission fault it sets a transmission related trouble code, the information is sent to the ECM and the ECM sets a P0700 trouble code as well.
Trouble Code P0700 is an informational code only. It doesn't point to a direct problem in the engine or transmission. Trouble Code P0700 only refers to a general transmission fault. A transmission scan tool will be required to further diagnose this fault.
