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2018 Elantra SEL: Car won't start, battery light on, and strange electrical issues

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Kevin B. · rep 0 · May 22, 3:00 AM · 1 replies · solved · Question

Vehicle: 2018 Hyundai Elantra SEL

Hey everyone,

My 2018 Hyundai Elantra SEL has been giving me a headache lately. A few mornings ago, it wouldn't start at all – just a click. I got a jump, and it started, but the battery light stayed on. Now, sometimes the radio cuts out briefly, and the power windows seem a bit sluggish.

I'm worried it's more than just the battery. Could it be the alternator? I've checked the battery terminals, and they seem clean and tight. Any ideas what might be going on before I take it to a shop?

Thanks for any help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:00 AM

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ClearTheCode admin answer:

It sounds like you're experiencing classic symptoms of a charging system issue, which could stem from several components. The battery light indicates a problem with the charging system, and the sluggish windows and radio cutting out further support this.

Here's what you can investigate:

  1. Check Battery Voltage: Even if jumped, a failing battery might not hold a charge. Use a multimeter to check the battery voltage with the engine off (should be around 12.6V) and then with the engine running (should be between 13.5V and 14.5V). If it's not charging while running, the alternator is suspect.
  2. Inspect Alternator Belt: Ensure the serpentine belt that drives the alternator is intact and properly tensioned. A loose or damaged belt can prevent the alternator from charging.
  3. Look for OBD Codes: A failing charging system often triggers specific diagnostic trouble codes (DTCs). Use an OBD-II scanner to check for codes like P0562 (System Voltage Low) or P0622 (Generator Field Control Circuit Malfunction). These codes can pinpoint the issue more accurately.
  4. Check Fuses: While less common for a full charging system failure, a blown fuse related to the alternator or voltage regulator could cause problems. Consult your owner's manual for the fuse box diagram.

Common Causes:

  • Failing Alternator: This is a very common cause for the symptoms you describe, especially with the battery light on and poor charging.
  • Weak or Failing Battery: Even if it takes a jump, the battery might not be able to hold a charge or deliver sufficient cranking amps.
  • Loose or Corroded Connections: Although you checked, double-check all battery terminals and the main ground strap from the battery to the chassis and engine.

When to See a Shop: If your multimeter tests show the alternator isn't charging, or if you're getting persistent charging system OBD codes after checking the basics, it's time to visit a qualified mechanic. A professional can perform more in-depth diagnostics on the alternator, voltage regulator, and wiring to accurately identify and repair the fault. Driving with a faulty charging system can leave you stranded and potentially damage other electrical components.

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