12.2021 Caterpillar ECM ECU Flash Files Full Set Download 

  1. Alternator failure (charging problem) 

 NOTE: This is not an electronic system problem. 

 (1) Possible reasons. 

 1) Alternator drive belt. 

 2) Charging circuit. 

 3) Regulator. 4) Alternator.  

 (2) Recommended measures. 

 1) Alternator drive belt. 

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 ① Check the condition of the alternator drive belt and replace it if it is worn or damaged. 

 ② Check the tension of the alternator drive belt. Adjust this tension if necessary. 

 2) Charging circuit. Check the battery cables, leads and connectors in the charging circuit. Clean and tighten all electrical connections. Replace all scrapped parts. 

 3) Alternator or regulator. Check that the alternator or regulator is working properly. Repair the alternator or replace the regulator if necessary. 

 2. Alternator failure (noise control) 

 NOTE: This is not an electronic system problem. 

 (1) Possible reasons. 

 1) Alternator drive belt. 

 2). Alternator drive pulley. 

 3) Alternator bearings. 

 (2) Recommended measures. 

 1) Alternator drive belt.  

① Check the condition of the alternator drive belt. If the alternator drive belt is worn or damaged, it should be replaced. 

 ② Check the tension of the alternator drive belt. Adjust this tension if necessary. 

 ③ Make sure the alternator drive belt is properly aligned. Check for broken or worn alternator mounting brackets. Repair or replace the alternator mounting bracket to ensure proper alignment of the alternator drive belt and alternator drive pulley.  

CAT Caterpillar ET 4 Diagnostic Adapter Truck Diagnostic Tool 

2) Alternator drive pulley. Loosen the nut on the alternator drive pulley and tighten the nut to the correct torque. 

 3) Alternator bearings. Check the alternator bearings for wear. Repair or replace the alternator if necessary.