Checking Components And Wiring

Check the signal line for open circuit, short-circuit to ground and short-circuit to voltage.

Take readings between:

• Engine Control Module (ECM) #B27 (#C27) and system relay #2.

Check the engine control module (ECM) and the system relay connector. Check for contact resistance. Check for oxidation.

Try a new system relay if no fault is found during the above fault-tracing.

Remedy as necessary.

Other information 

• see CONNECTING THE BREAKOUT BOX
• see SIGNAL SPECIFICATION
• see CHECKING WIRING AND TERMINALS

Fig 1: Identifying Main Relay

Courtesy of VOLVO CARS CORPORATION

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  Refer to INFORMATION