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2018 RX 350 Battery Draining Fast & 'Check Charging System' Light On

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Sarah K. · rep 0 · May 22, 4:43 AM · 1 replies · solved · Question

Vehicle: 2018 Lexus RX 350 F Sport

Hey everyone,

I've been having a frustrating issue with my 2018 Lexus RX 350 F Sport lately. The battery seems to be draining really fast, sometimes even overnight. I've had to jump-start it a couple of times this week, which is not ideal.

To make things worse, the 'Check Charging System' warning light has started appearing on my dashboard. I'm worried it might be the alternator, but I'm not sure. Has anyone else experienced this with their RX 350 or a similar Lexus model? Any ideas on what could be causing this or what I should check first before taking it to the dealer?

Thanks for any help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:43 AM

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ClearTheCode admin answer:

This sounds like a classic charging system issue, which can be caused by several components. Here's a breakdown of potential causes and steps:

Diagnostics & Causes:

  1. Battery Health: Even if it's being charged, a weak or old battery might not hold a charge effectively. A simple battery test at an auto parts store can confirm its condition.
  2. Alternator Failure: The 'Check Charging System' light strongly points to the alternator. Its job is to generate electricity to power the car's electrical systems and recharge the battery. If it's failing, the battery will drain as it's not being replenished.
  3. Loose or Corroded Connections: Check the battery terminals and alternator connections for any looseness or corrosion. Poor contact can impede charging.
  4. Parasitic Draw: Less common but possible, a component might be staying on and drawing power even when the car is off. This requires more advanced electrical testing.

OBD Codes: If you have access to an OBD-II scanner, look for codes like:

  • P0562: System Voltage Low
  • P0622: Generator L-Terminal Circuit
  • P0620: Generator Control Circuit Malfunction

When to See a Shop: Given the 'Check Charging System' light and repeated draining, it's highly recommended to have your 2018 Lexus RX 350 inspected by a qualified mechanic or Lexus dealership as soon as possible. Driving with a failing charging system can leave you stranded and potentially damage other electrical components due to unstable voltage. They can perform a comprehensive charging system test to pinpoint the exact fault, whether it's the battery, alternator, voltage regulator, or wiring.

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