Checking Relay And Start Relay Control Signal

CAUTION:

Avoid touching the pins in the control module and the corresponding connector on the cable harness.

There is a risk of static discharge which could damage the control module.

Discharge yourself and tools to be used by holding the tool's metal part and touching a body part on the car just before starting to work.

It is possible to deduce whether the fault is in the wiring or in the relay by connecting a electrician's screwdriver over the relay socket coil.
For vehicles with automatic transmission:
The gear selector shall be in position P or N.
For vehicles with manual transmission:
The gear lever shall be in neutral position.
Parking brake applied.
Connect a test probe between relay connection #1(86) and #2(85) on the relay socket.

Turn the ignition to start position (ignition position III) and observe the light.

If test probe lights up, replace the relay.

If test probe does not light up:
- Check fuses.
- Check the cable between the ignition's 50-feed #B2 and Central Electronic Module (CEM) #A42 for short-circuiting to ground and open circuit.
  Check the cable between Central Electronic Module (CEM) #E9 and the relay socket #1(86) for short-circuit to ground and open circuit.
- Check the cable between relay socket #2(85) and Engine Control Module (ECM) for short-circuit to voltage and open circuit.
- Check the connector for the ignition for contact resistance as well as damage to pins and connections.
  Check the connector for the Central Electronic Module (CEM) with regards to contact resistance as well as damage to pins and connections.
  
  Check the connector for Engine Control Module (ECM) for contact resistance as well as damage to pins and connections.
Remedy as necessary.

Fig 1: Identifying Starter Motor Relay
Courtesy of VOLVO CARS CORPORATION

Was a fault detected?