Data Link Connector, A/T

PIN 1 - (Not used)
PIN 2 - J185O Bus + L line on 2-wire systems, or single wire (Class 2)
PIN 3 - (Not used)
PIN 4 - Chassis ground pin
PIN 5 - Signal ground pin
PIN 6 - [1][2]PCM diagnostic enable
PIN 7 - (Not used)
PIN 8 - (Not used)
PIN 9 - Primary UART
PIN 10 - (Not used)
PIN 11 - (Not used)
PIN 12 - ABS diagnostic or CCM diagnostic enable
PIN 13 - SIR diagnostic enable
PIN 14 - (Not used)
PIN 15 - (Not used)
PIN 16 - Battery power from vehicle unswitched (4 AMP MAX)