TECH TIP
Chevy Malibu Alternator Not Charging
Feb. 02 2021
Feb. 02 2021

Vehicle: 2014 Chevrolet Malibu, L4-2.5L, Automatic Transmission

Mileage: 107,854

Problem: This Chevy Malibu was towed to the shop with a "no crank" condition. The vehicle owner had replaced the battery. Immediately afterwards, the engine started up and ran but quickly died and the engine would not crank over.

Case Details: Once in the shop, the technician tested the charging system and found that the alternator wasn’t charging. After connecting a scan tool, he found that there were multiple diagnostic trouble codes (DTCs).

  • C0800 - Control Module Power Circuit
  • U0184 - Electronic Brake Control Module (EBCM)
  • B144B - Run/Crank Power Relay Circuit
  • B1517 - Battery Voltage
  • B257B - Lighting Control Switch Signal
  • B2955 - Security Sensor Data Circuit
  • B3006 - Hood Ajar Circuit
  • C0890 - Control Module Voltage Reference Output 3 Circuit voltage
  • B101E - Electronic Control Unit Software
  • B1325 - Control Module Power Circuit

The technician didn’t see a common relationship between the DTCs, so he called ALLDATA Tech-Assist to help sort it all out. The Tech-Assist consultant told the technician that this vehicle had two batteries because it was equipped with a Start/Stop system (based on RPO code KL9). He advised checking the main and auxiliary batteries. If both were good, then clear the DTCs and reset the charging system. He added that the charging system wouldn’t work until all the DTCs were cleared.

Confirmed Repair: The technician found that it was the main battery that had been replaced. He charged the main battery and tested the auxiliary battery. The auxiliary battery was in good shape, so he cleared all the DTCs and reset the charging system. After that, the alternator was charging both batteries at 13.9 volts and the DTCs did not return after a test drive. 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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