Check regulation voltage of alternator

AR15.40-P-5010FF

Check regulation voltage of alternator

19.11.04



Check

 Danger!

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 engine

Secure vehicle to prevent it from moving.
Wear closed and snug-fitting work clothes.
Do not grasp hot or rotating parts.

AS00.00-Z-0005-01A

1

Check whether the preconditions for the alternator test have been satisfied

AR15.40-P-5009FF

2

Check condition of battery (G1)

AR54.10-P-1129FF

3

Connect multimeter (1) according to connection diagram



*WH58.30-Z-1001-09A

4

Start engine

5

Check charge indictor when engine idling and when engine speed increased (up to 3000 rpm)

 In case of correct charging voltage, no fault message is shown in the display of the instrument cluster.

6

Check regulation voltage

 Load battery (G1) by means of a permanent consumer.

*BE15.40-P-1001-02G

If the regulation voltage is > 14.7 V, the alternator (G2) should be replaced. Refer to:

Remove and install alternator

Engine 122

AR15.40-P-5032FB

Engines 134, 135

AR15.40-P-5032FF

Engine 639

AR15.40-P-5032FG

If the regulation voltage is < 13.0 V: 

1. Remove transition resistors at the electrical connections of the charging system and check regulation voltage again.

2. If the regulation voltage is still below
< 13.0 V, the alternator (G2) must be replaced. See:

Remove and install alternator

Engine 122

AR15.40-P-5032FB

Engines 134, 135

AR15.40-P-5032FF

Engine 639

AR15.40-P-5032FG

7

Turn off engine

8

Disconnect multimeter (1)



*WH58.30-Z-1001-09A

9

Close engine hood

Number

Designation

Engines
134, 135,
639
in model
454

Engine
122
in model
454

BE15.40-P-1001-02G

Regulating voltage
(at battery)

Loading: only
on permanent consumer

V

13...14.7

13...14.7

Engine speed

rpm

3000

2500

measured after

min

2

2

Number

Designation

WH58.30-Z-1001-09A

Multimeter