TJ. MFI#9
MFI #9 Main relay power supply absent
Conditions for fault messages:
Fault message is logged if voltage is under 1 V.
Causes of fault:
Break in the [1][2]system relay.
Break in the wiring between MFI#21 and [1][2]system relay.
Fault symptoms:
The engine will not start.
If the fault is intermittent the engine will stop or run rough.
TJ1
Volvo ST, Test Box
-Disconnect the ST in accordance with QA2. Connecting The Volvo Scan Tool (ST)
-Connect the test box to MFI and check GND points in accordance with P1-P2.
-Continue with Checking the power supply MFI#21 TJ2.
TJ2
Checking The Power Supply MFI#21
-Connect the control module to the test box.
-Re-install system fuse.
-Ignition off.
Connect a voltmeter between MFI#21 and MFI#5.
The voltmeter should read battery voltage.
If this value is OK:
-Check the control of MFI #21 TJ3.
If the reading is incorrect:
-Test [1][2]system relay MFI#21 TJ6.
TJ3
Checking The Control Of MFI#21
-Ignition on.
The voltmeter should read approx. 0.8 V.
If this value Is OK:
-Check MFI#9 TJ4.
If the reading is incorrect:
-Try using a new control module.
TJ4
Checking MFI#9
-Ignition on.
Connect a voltmeter between MFI#g and MFI#5.
The voltmeter should read battery voltage.
If this value is OK:
Intermittent fault.
-Check the connections to MFI#21 and MFI#5 for loose contacts.
If the reading Is incorrect:
-Test the [1][2]system relay MFI#9 SG5.
TJ5
Testing The [1][2]System Relay MFI#9
-Try using a new [1][2]system relay.
Connect a voltmeter between MFI#9 and MFI#5.
The voltmeter should read battery voltage.
If this value is OK:
-The [1][2]system relay was broken.
If the value Is still incorrect:
-Check the wiring between MFI#9 and the [1][2]system relay for breaks in accordance with NA2. Checking the Wiring
-Install the old relay.
TJ6
Test [1][2]System Relay MFI#21
-Try using a new [1][2]system relay.
-Ignition off.
Connect a voltmeter between MFI#21 and MFI#5.
The voltmeter should read battery voltage.
If this value is OK:
-The [1][2]system relay was broken.
If the value is still incorrect:
-Check the wiring between MFI#21 and the fuse via the [1][2]system relay for breaks in accordance with NA2. Checking the Wiring
-Install the old relay.