Ram 3500 Strange Charging System Issue – MIL On
Jan. 03 2023
Jan. 03 2023

Vehicle: 2013 Dodge Ram 3500, 4WD, L6-6.7L DSL Turbo, Automatic transmission/transaxle

Mileage: 134,876

Problem: The customer brought his Ram 3500 to the shop because the MIL was on and he noticed that every time he started the engine, there was a very brief "Charge Battery" message in the instrument cluster. NOTE: This truck was equipped with a dual battery starting/charging system. The customer added that the truck ran fine with no drivability issues.

Case Details: The technician checked the charging system and batteries first and found no apparent issues. Next, he connected a scan tool and retrieved two diagnostic trouble codes (DTCs).

  • P0562 - System Voltage Low
  • P2509 - PCM/PCM Power Input Signal Intermittent

The charging system test results and DTCs seemed to contradict each other, so the technician called an ALLDATA Tech-Assist consultant who gave him additional diagnostic advice and testing procedures.

The consultant mentioned that those two DTCs were common with weak or discharged batteries. The DTCs combined with the “Charge Battery” warning message indicated that the technician should inspect both batteries again using the following recommended battery tests:

  • Inspect all cables and connections to make sure they are clean, tight and free from corrosion.
  • Check the voltage of each battery during a cranking event, then load test each battery.

The technician checked the cables and connections before testing the batteries as the consultant suggested. The cables and connections were in good condition, but the driver's side battery failed the load test.

Confirmed Repair: The technician replaced the battery, cleared the DTCs and started the engine numerous times in the shop. The MIL and “Charge Battery” message did not return. He also took the truck on a road test. It ran fine. Fixed!

The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips 

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