Diagnosis the engine starting system

Diagnosis failures engine starting system

Body ground

Starter ground

Engine groundBody ground

BATTERY

M

CBA

Ground Plate Ground pigtail

Tests to be performed according to the detected failure

1. Turning the key in start position the starter doesn’t run and the solenoid doesn’t switch on.

The following tests should be performed:

• Test 0• Test 4• Test 5• Test 7• Test 8• Test 9• Test 10• Test 11

2. Turning the key in start position the starter doesn’t run, but the solenoid switches on.

The following tests should be performed:

• Test 0• Test 1• Test 2• Test 3• Test 4• Test 5• Test 6• Test 7• Test 9

Tests to be performed according to the detected failure

3. Turning the key in start position the starter runs slowly.

The following tests should be performed:

• Test 0• Test 1• Test 3• Test 4• Test 5• Test 6• Test 7• Test 12

4. Turning the key in start position the starter sometimes doesn’t run.

The following tests should be performed:

• Test 0• Test 1• Test 3• Test 4• Test 5• Test 6• Test 7• Test 9• Test 10• Test 12

Test 0: Check battery voltage

• Check the battery voltage level.• The battery voltage level must not

be under 12,3 volt.

Failure 1: Go to Test 4

Failure 2: Go to Test 1

Failure 3: Go to Test 1

Failure 4: Go to Test 1

Test 1: Check CBA nuts tightening

• Check the tightening torque of the two nuts of the 500 A fuse in the CBA as shown in the picture.

• The correct tightening torque must be equal to 11 ± 2,2 Nm

Failure 2: Go to Test 2

Failure 3: Go to Test 3

Failure 4: Go to Test 3

Test 2: Check efficiency 500 A fuse

• Check with a tester the current conduction of the 500 A fuse between the two points as shown in the picture

• Attention: please note that the 500 A fuse with PN 42556405 was substituted by the new PN 42560737 from Chassis 5775801 (Suzzara) and D405152 (Valladolid) in date October 2008

Go to Test 3

Test 3: Check the tightening torque of supply cable nuts on the battery and on the derivation junction

• Check the tightening torque of the three nuts shown in the pictures

• The tightening torque of the battery power supply cable must be equal to 5,5 Nm

Go to Test 4

The tightening torque of the wires fixing nuts on the derivation junction must be equal to 11 ± 2,2 Nm

Test 4: Check tightening torque and electrical function of the ground wiring loom

Check by disconnecting the engine ground wiring loom that the area of electrical contact is not rusty, dirty or grease contaminated.

Check the tightening torque of the nut on the engine side

The correct tightening torque must be equal to:

F1A engine 33,5 ± 6,6 Nm, F1C engine 40,5 ± 8 Nm

Go to Test 5

Test 5: Check starter motor nuts tightening

• Check the starter motor nuts tightening of the (+30) red wire and (+50) wiring loom.

• The correct tightening torque must be equal to 15 ± 3 Nm.

Failure 1: Go to Test 7

Failure 2: Go to Test 6

Failure 3: Go to Test 6

Failure 4: Go to Test 6

Test 6: Check overheating on (+30) starter wire

• Check the (+30) red wire on starter for any signs of overheating.

Go to Test 7

Test 7: Check starter motor case

• Check that the case of the starter motor does not show evident signs of rust or corrosion.

Failure 1: Go to Test 8

Failure 2: Go to Test 9

Failure 3: Go to Test 12

Failure 4: Go to Test 9

Test 8: Check water infiltration in the OPT fuse box

T18

1. Only for vehicles fitted with starter protection relay (T18):

Remove the cover of OPT box and verify the area shown in the figure, together with the relay T18, for signs of water or deposits due to infiltration.

Go to Test 9

Test 9: Check the ignition lock for jamming

• Start the engine and verify that returning the ignition key to the “key on” position (execute the operation very slowly) the ignition lock is not jamming at any time.

• Repeat the operation for at least ten times.

Failure 1: Go to Test 10

Failure 2: End of check

Failure 4: Go to Test 10

Test 10: Check the terminals of the 4-way ignition lock connector

• Check that the terminals of the 4-way ignition lock connector are not loose or oxidized

12

34

Failure 1: Go to Test 11

Failure 4: Go to Test 12

Test 11: Check current conduction of the connector between ignition lock and starter motor

• Verify with a tester the current conduction between pin 2 of the 4-way ignition lock connector and the (+50) starter motor wire

2

End of check

Test 12: Check starter motor voltage between +50 and ground

• By ignition key in engine start position check with a tester the starter motor voltage between (+50) and ground.

End of check

  Volts OK KO

Test 0 Check battery voltage Measured voltage      

  YES NO

Test 1 Check CBA nuts tightening Fixing correct?    

  YES NO

Test 2 Check efficiency 500 A Fuse Fuse blown?    

  YES NO

Test 3 Check tightening torque of the power

supply cable nutsFixing correct?    

  YES NO

Test 4 Check tightening torque and electrical

function of the ground wiring loom

Fixing correct?    

Electrical function?    

  YES NO

Test 5 Check starter motor nuts tightening Fixing correct?    

  YES NO

Test 6 Check overheating on (+30) starter wire Overheating?    

Report diagnosis engine starting system

Report diagnosis engine starting system

  YES NO

Test 7 Check starter motor case Signs of oxidation / rust?    

  YES NO

Test 8 Check water infiltration in the OPT fuse

box Signs of infiltration?    

  YES NO

Test 9 Check the ignition lock for jamming Ignition lock jams ?    

  If so what? YES NO

Test 10

Check the terminals of the 4-way ignition lock connector

Failures found?      

  YES NO

Test 11

Check current conduction of the connector between ignition lock and starter motor

Electrical function?    

  Volts    

Test 12

Check starter motor voltage between +50 and ground

Measured voltage