Checking power supply

• Connect multimeter as follows to measure voltage.
  ECM POWER SUPPLY RELAY CIRCUIT TEST: POWER SUPPLY
  
  

  Relay carrier in electronics box, plenum chamber, position 2 terminal	Measure to
  1	Engine ground
  2	Engine ground

  Fig 1: Identifying Power Supply Relay Harness Connector Terminals

  Courtesy of AUDI OF AMERICA, INC.
  • Specified value: approx. battery voltage

If specified value is not obtained:

• Check wiring connections.