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Test Alternator Charging Current - AR15.40-P-5011W

ENGINES 152, 276 in MODEL 172 

Connection scheme 

G13845501Courtesy of MERCEDES-BENZ USA
INSPECT Checking    
Risk of injury  caused by fingers being pinched or crushed when removing, installing or aligning hoods, doors, trunk lids, liftgates or sliding roof Keep body parts and limbs well clear of moving parts. AS00.00-Z-0011-01A
Risk of death  caused by vehicle slipping or toppling off of the lifting platform. Align vehicle between columns of vehicle lift and position four support plates at vehicle lift support points specified by vehicle manufacturer. AS00.00-Z-0010-01A
1 Check tension of poly-V belt    
2 Check poly-V belt for wear   AP13.22-P-1352V
3 Check electrical lines to on-board electrical system battery (G1), alternator (G2), starter (M1) and on the ground point for the battery at the front right (W10) in the engine compartment for tight seating and check for a perfect condition    
4 Remove bottom engine compartment paneling   AR61.20-P-1105W
5 Check ground strap between engine and body for tight seating and proper condition    
6 Connect volt ampere tester (079) with current clamp (065) according to connection diagram    
Risk of accident  caused by vehicle starting off by itself when engine is running. Risk of injury  caused by contusions and burns during starting procedure or when working near the engine as it is running Secure vehicle to prevent it from moving by itself.
Wear closed and snug-fitting work clothes.
Do not touch hot or rotating parts.
AS00.00-Z-0005-01A
7 Start engine
8 Test charge current at high engine revs; apply load to on-board electrical system battery (G1) for this step using volt-ampere tester (079) IMPORTANT Vary load resistance until the maximum load current is achieved; in doing so, the regulation voltage must not fall below 12.7 V.
Check values for the ALT (G2) Charge rate below specified value: ↓
*BE15.40-P-1001-01L 
    Test alternator diodes (G2).
If diodes are faulty:

Replace alternator (G2V
AR15.40-P-9301-02W 
    Engine 276 AR15.40-P-5032W 
    Engine 152 AR15.40-P-5032MMI
9 Turn off engine    
10 Disconnect volt ampere tester (079) with current clamp (065)    
CHECK VALUES FOR ALTERNATOR

Number Designation Engine 276 in model 166, 172, 204, 207, 212, 218 Engine 152 in model 172
BE15.40-P-1001-01L Charge current for alternator max. A 180 180
min. A 140 140
Engine speed RPM 2000 2000
Ratio i= 2.93 2.93