Checking the power supply and ground for the engine control module (ECM)

Checking the power supply 

• Check the fuse for the engine control module (ECM) in the fusebox in the engine compartment. See approbate Wiring diagram Service Manual. If the fuse is blown, check the circuit after the fuse. Check for a short-circuit to ground.
• Check the power supply to the engine control module (ECM). The voltage must be approximately battery voltage.

Checking the ground terminal 

• Check the ground leads between the engine control module (ECM) and the ground terminal. Check for an open-circuit
• Check the ground terminal for the engine control module (ECM). Check for contact resistance and oxidation.

Remedy as necessary

Other information 

• See Connecting the breakout box
• For information about signals, see ELECTRICAL SYSTEM
• For information about the circuit, see the relevant Wiring diagram.
• For information about the location of the ground terminal see the relevant Wiring diagram.

Fig 1: Identifying Breakout Box

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Engine Control Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

Was a fault detected? 

• YES 

  Refer to Checking the engine control module (ECM) 

• NO 

  Refer to Checking communication with the engine control module (ECM)