The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

Battery Warning Light On in 2020 Mazda 6, Slow Cranking

0

Eric V. · rep 0 · May 22, 4:50 AM · 1 replies · solved · Question

Vehicle: 2020 Mazda 6 Signature

My 2020 Mazda 6 Signature recently started showing the battery warning light on the dash. It's a solid red light, and it came on a couple of days ago. I've also noticed the car cranking slowly, especially in the mornings, which makes me nervous about getting stranded.

I took it to a local auto parts store, and they tested the battery, saying it was okay. However, the light is still on, and the slow cranking hasn't improved. Could this be an alternator issue, or is there something else electrical I should be looking into? I want to address this before it becomes a bigger problem.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:50 AM

0

ClearTheCode admin answer:

A battery warning light, especially coupled with slow cranking, almost always points to an issue within the charging system, even if the battery itself tests 'okay' initially. Here's a breakdown of potential causes and steps:

  1. Re-evaluate Battery Health: While the auto parts store said it was okay, a battery under load can behave differently. Ensure the battery terminals are clean and tight. A weak battery can still cause issues, especially if it's nearing the end of its life (typically 3-5 years).
  2. Alternator Output Test: The most common culprit for a battery light is a failing alternator. It might not be producing enough voltage to charge the battery effectively. A professional shop can perform a comprehensive alternator output test while the engine is running.
  3. Serpentine Belt Inspection: The alternator is driven by the serpentine belt. Check the belt for cracks, fraying, or excessive looseness. If the belt is slipping, the alternator won't spin fast enough to charge.
  4. Wiring and Fuses: Inspect the wiring connected to the alternator and battery for any signs of corrosion, damage, or loose connections. Also, check the main fuse for the charging system, usually located in the under-hood fuse box.
  5. OBD-II Scan: Even without a check engine light, a scan tool can reveal charging system-related codes. Look for codes such as:
    • P0562: System Voltage Low
    • P0620: Generator Control Circuit Malfunction
    • P0622: Generator Field 'F' Control Circuit Malfunction

When to See a Shop: Given the persistent light and slow cranking, it's highly recommended to have your Mazda 6 inspected by a qualified mechanic or Mazda dealership as soon as possible. Driving with a failing charging system can lead to a complete breakdown, as the battery will eventually drain and the car will lose power. They can accurately diagnose whether it's the alternator, voltage regulator, wiring, or a more subtle battery issue.

Menu

Help & account