Trouble Code 300 (Diagnostic Link Defective)
DIAGNOSTIC LINK DEFECTIVEExplanation
The diagnostic link TxD or RxD has a break or has a short to positive or ground.
The TxD link leads from the diagnostic socket Pin 20 to the Electronic Transmission Control (EGS) control unit Pin 13 and is bypassed to ground when the cover is closed.
The RxD link leads from the diagnostic socket Pin 15 to the EGS control unit Pin 25 and is bypassed to terminal 30 when the cover is closed.
Troubleshooting
Check wire.