Engine Electrics (Check alternator): Repair Instructions

Electrolyte level at least

5 mm above the

Fill with distilled water up to marking or

plate or separator

Check electrolyte density if possible

Charge battery

Minimum thickness 1.24 g/cm ³

Measure control voltage

Charge battery

Test battery with tester KM-J-42000

Measure control voltage

Replace defective battery

• Is battery connected to vehicle electronics?
• Ground connection battery/engine/body has good connection and is free from corrosion/transfer resistance?
• All alternator-related wiring harness plugs are properly seated and free from corrosion/transfer resistance.
• V-belt tension OK

• Connect battery
• Clean/replace ground connection battery/engine/body.
• Clean/replace wiring harness plugs
• Ensure V-belt tension complies with auto manufacturer data

Measure control voltage:

• Start cold engine (no consumers)
• Engine speed 2000 rpm
• Measure control voltage at alternator B+ connection and alternator housing (not at battery terminals).
• Control voltage: 13.7 - 14.8 V

Replace regulator/alternator

Output check:

• Position clamp-on ammeter as close to alternator B+ connection as possible
• Measure voltage at B+ and alternator housing
• Start engine
• Engine speed approx. 2000 rpm
• Switch on all consumers in vehicle
• During this time, control voltage must not drop below the test values.

Replace alternator

Check alternator with oscilloscope

Replace alternator