Isuzu KB P190. Manual - part 398

6D-4  ENGINE ELECTRICAL (4JK1/4JJ1) 

Charging System (4JK1) 

 

 
 
 
 
 

 

 

RTW56DMF000601 

Charging System (4JJ1) 

 

 

 

RTW56DMF000101 

ENGINE ELECTRICAL (4JK1/4JJ1)  6D-5 

Troubleshooting 

Symptoms 

• No 

charging 

• Inadequate 

charging 

• Excessive 

charging 

•  Unstable charging current 
•  Abnormal generator noise 

 
 

6D-6  ENGINE ELECTRICAL (4JK1/4JJ1) 

No charging 

Possible problem 

Countermeasure 

Dead battery 

Replace  

Open or shorted wiring 

Open or shorted ammeter 

Loose wiring connections 

Repair 

One or more generator coils open or shorted 

Bad diode 

Bad regulator 

Replace 

Loose regulator connections 

Repair 

 
Inadequate charging 

Possible problem 

Countermeasure 

Dead battery 

Replace 

Open or shorted wiring 

Loose wiring connections 

Repair 

Loose generator drive belt 

Adjust belt tension 

Stator coil intermittent short 

Bad diode 

Replace 

Loose battery connections 

Repair 

Bad regulator 

Replace 

Loose regulator connections 

Repair 

 
Excessive charging 

Possible problem 

Countermeasure 

Bad regulator 

Replace 

 
Unstable charging current 

Possible problem 

Countermeasure 

Open wiring connection or broken wire 

Repair 

Loose generator drive belt 

Adjust belt tension 

Open or shorted stator coil 

Replace 

Loose terminal connections 

Repair 

Bad regulator 

Replace 

Loose regulator terminal connections 

Repair 

 
Abnormal operating noise 

Possible problem 

Countermeasure 

Loose generator drive belt 

Adjust belt tension 

Bad bearing 

Replace 

Loose rotor core or stator core 

Repair 

Bad diode 

Replace 

Open or shorted stator coil 

Replace 

 

ENGINE ELECTRICAL (4JK1/4JJ1)  6D-7 

Diagnosis 

On-vehicle Inspection 

The charging system warning light tells the vehicle
operator of possible problems with the system. 

 

When the ignition switch is moved to the ON position,
the light turns on. The light turns off immediately after
the engine is started. If the light turns on during engine
operation, there is a problem with the charging system.
Perform the checks described below. 

 

1.  Check the belt (broken or loose). 

2. 

Check the harness connectors (loose or

disconnected). 

3.  With the engine off, turn the ignition switch to the

ON position. If the warning lamp does not light,

remove the harness connector from the generator.

Ground the connector IG terminal. The lamp

should light. If it does not, the bulb is burned out.

Replace the bulb. 

4.  Start the engine. If the warning lamp remains on,

the generator must be repaired or replaced.