Checking ignition coil Ground wire

• Disconnect 4-pin connector at relevant ignition coil.
  Fig 1: Identifying Ignition Coil 4-Pin Harness Connector Terminals

  Courtesy of AUDI OF AMERICA, INC.
• Check for open circuit and short to positive in Ground connection from socket 4 of 4-pin connector to engine Ground.
• Eliminate open circuit in wiring/short circuit if necessary.

If Ground connection is OK:

• Check power supply of ignition coil. See CHECKING POWER SUPPLY OF IGNITION COIL .