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Home >> Volvo >> 2009 >> C70 T5 L5-2.5L Turbo VIN 67 B5254T7 >> Repair and Diagnosis >> Starting and Charging >> Starting System >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Check the Start System >> Part 2

Part 2






Check the start system (Continued)

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.

Other information
- See Connecting breakout box for Central Electronic Module (CEM).
- See Connecting breakout box for Engine Control Module (ECM).
- See Signal specification for Central Electronic Module (CEM).
- See Signal specification for Engine Control Module (ECM).
- For connecting test probe, use loose flat pins.
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.
- Checking wiring and terminals Checking Wiring and Terminals





Was a fault detected?

Yes - Verification

No - Other fault-tracing

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Checking the wiring




- Ignition off.
- 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.
Maintain the short-circuit between relay socket #3(30) with #5(87).
Check that there is power supply to the starter motor #6/25:2(#A1).
Check that the voltage is approximately battery voltage.

If there is no voltage supply to the starter motor terminal #6/25:2(#A1):
- Check fuses.
- Check the cable between connector 64/90 and starter motor #6/25:2(#A1) for short-circuit to ground and open circuit.
- Check the connector to the starter motor terminal #6/25:2(#A1). Check for contact resistance and damage to pins and connections.
Check that there is a power supply to the starter motor terminal #6/25:1(#B1).
Check that the voltage is approximately battery voltage.

If there is no voltage supply to the starter motor terminal #6/25:1(#B1):
- Check fuses.
- Check the voltage feed cable between the battery and starter motor #6/25:1(#B1) for short-circuit to ground and open circuit.
- Check the connector to the starter motor terminal #6/25:1(#B1). Check for contact resistance and damage to connections.
Remedy as necessary.

Other information
- See Connecting breakout box for Central Electronic Module (CEM).
- See Connecting breakout box for Engine Control Module (ECM).
- See Signal specification for Central Electronic Module (CEM).
- See Signal specification for Engine Control Module (ECM).
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.
- Checking wiring and terminals Checking Wiring and Terminals





Was a fault detected?

Yes - Verification

No - Other fault-tracing

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Checking the starter motor





Note! To carry out this test, the battery must be fault free and the starter motor relay must be checked and there must be no diagnostic trouble codes (DTCs) stored for the symptom.

Warning! If the engine cooling fan is running, wait until it has stopped.




- Ignition off.
- 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.
- The function of the control solenoid must be checked by temporarily bridging the power supply between terminal #6/25:1(#B1) and the control signal for the starter motor relay terminal #6/25:2 (#A1).
The control solenoid must click and the starter motor must turn.

Other information
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.





Does the starter motor turn?

Yes - Voltage drop in wiring to starter motor

No - Checking the starter motor

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Voltage drop in wiring to starter motor








- Ignition off.
- Reinstall the connectors, components etc.
- Connect a voltmeter to starter motor terminal #6/25:2(#A1).
- Check the voltage to the starter motor terminal #6/25:2(#A1) in the start position (ignition position III).
If the voltage drops below approximately 9 V, there is a voltage drop in the wiring circuit to the starter motor.

Select an option:
1. Malfunction was found in the test, that is, the voltage dropped too low in the start position.
2. No malfunction was found in the test, that is, the voltage did not drop too low in the start position.

Other information
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.





1 - Check the voltage drop in the starter motor and battery circuit

2 - Other fault-tracing

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Check the voltage drop in the starter motor and battery circuit




- The battery shall be fully charged.
- The vehicle and engine temperatures must be above 20 °C (68 °F).

Warning! If the engine cooling fan is running, wait until it has stopped.

- Ignition off.
- 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.
- Remove the starter motor relay.
- Expose the battery.
- Connect a voltmeter between the battery positive and negative terminals.
- Temporarily connect two cables to relay base terminal #3(30) and terminal #5(87).
Use two cables with suitable cable terminal when short-circuiting so that the spark does not damage the relay socket.
Check the voltage of the battery when the starter motor is operating. Temporarily short-circuit the cables to each other so that the control solenoid draws power and the starter motor starts.
Make a note of the value!

Note! Do not bridge directly in the relay socket. Contacts may be damaged.

The voltage may deviate slightly depending on the engine's compression stage.
Therefore, an average value shall be taken.
Connect a voltmeter between starter motor voltage supply terminal #6/25:1(#B1) and the engine block.
Check the voltage across the starter motor when it works by temporarily shorting the cables to each other so that the control solenoid is activated and the starter motor starts.
Make a note of the value!
The difference between the voltage of the battery and starter motor must not exceed 1 V.
If the difference is greater this is due to too high frequency in the starter motor supply and ground circuit.
If the value is OK there is no voltage drop in the starter motor or battery circuit.
Option Yes below finishes fault-tracing for the starter motor.
If the value is not OK there is a voltage drop in the starter motor and battery circuit.
Option No below leads to fault-tracing with regard to voltage drop in the starter motor and the battery circuit.

Other information
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.





Is the value OK?

Yes - Fault tracing for the starter motor complete.

No - Checking the wiring and connections in the positive and negative circuits

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Checking the wiring and connections in the positive and negative circuits













When the voltage drop is too high this means too high resistance in the circuit.
The ground terminals are an important part of the vehicle's electrical system.
All sub-system voltage levels refer to the vehicle's ground terminals (as 0 V).
The three figures show grounding point bolted joint for engine block (the left figure) and body (the right figure),as well as the current's path in the joints.
If there is inadequate ground connection contact, this will have a negative impact on the electrical system.
It is very important that the ground connection is correct, that is, that frame screws are adequately tightened and that the cable terminals at the connections are correctly contact-pressed.
Grounding point where several cables are interconnected is of special importance.

Note! There must not be any corrosion between the cable terminals and screw heads.

Check the starter motor connection for voltage supply and connection to the engine block. Check for contact resistance and oxidation.
Check the connections of the terminals to the cables.
Check the engine's ground connection for contact resistance and oxidation.
Check the connections of the terminals to the cables.
Check the positive and negative terminals of the battery. Check for contact resistance and oxidation.
Check the connections of the terminals to the cables.
Check the connection for the battery negative lead to the body.
Remedy as necessary.

Other information
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.
- Checking wiring and terminals Checking Wiring and Terminals

Continue - Verification

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Checking the starter motor
Check the voltage feed cable between the battery and starter motor #6/25:1(#B1) for short-circuit to ground and open circuit.
Check fuses.
If the starter motor does not work when bridging between terminal #6/25:1(#B1) and terminal #6/25:2(#A1), despite being supplied with voltage from the battery, there is an internal fault.
Replace starter motor.
Remedy as necessary.

Other information
- For information about the cable routing, see the relevant Wiring Diagram.
- For further information about the fuses and relays, see the Wiring Diagram.
- Checking wiring and terminals Checking Wiring and Terminals





Continue - Verification

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