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2018 Model 3 Reduced Power & Warning Lights

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Mike T. · rep 0 · May 25, 3:59 AM · 1 replies · solved · Question

Vehicle: 2018 Tesla Model 3 Long Range

Hey everyone,

My 2018 Tesla Model 3 Long Range just threw a major fit. While driving on the highway, I suddenly got a "Reduced Power" alert on the screen, along with several yellow warning lights. The car felt sluggish and wouldn't accelerate properly.

I managed to get it home, but now I'm seeing a "Service Required" message. It's an intermittent issue; sometimes it drives fine for a bit, then it happens again. No strange noises, just the power reduction and warnings.

Has anyone experienced this with their Model 3? What could be causing it? I'm worried about driving it.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:59 AM

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ClearTheCode admin answer:

Experiencing reduced power and warning lights in your 2018 Tesla Model 3 can be concerning. This often indicates a critical issue detected by the vehicle's onboard diagnostic system, likely related to the high-voltage battery system or powertrain.

  1. Check Diagnostic Alerts: Tesla vehicles display specific alerts on the touchscreen that can provide more detail than generic OBD-II codes. Look for messages related to the battery, motor, or drive unit. These often come with an alphanumeric code that Tesla service can interpret.

  2. Potential Causes:

    • Battery Management System (BMS) Fault: The BMS monitors individual battery cells. A fault here can trigger a protective reduced power mode to prevent damage.
    • Motor or Inverter Issue: Problems with the electric motor or its inverter (which converts DC battery power to AC for the motor) can severely limit power output.
    • High Voltage Contactor Failure: These contactors connect the battery to the rest of the high-voltage system. If one fails, it can cut power.
    • Sensor Malfunction: A faulty sensor in the powertrain or battery system could be sending incorrect data, causing the car to enter limp mode.
    • Software Glitch: While less common for persistent issues, a software bug could potentially trigger false warnings.

  3. When to See a Shop: Given the intermittent nature and the "Service Required" message, it's crucial to address this immediately. Driving with reduced power can be unsafe, and ignoring critical warnings can lead to further damage. You should:

    • Schedule Service: Contact Tesla service directly through your app to schedule a diagnostic appointment. Provide them with details of the alerts and symptoms.
    • Avoid Driving: If the reduced power mode is frequent or severe, avoid driving the vehicle until it has been inspected. If you must drive, do so cautiously and for short distances.

Tesla's diagnostic tools are proprietary and can pinpoint these issues precisely. They will be able to read the specific fault codes logged by your vehicle and recommend the necessary repairs, which could range from a software update to a component replacement within the high-voltage system.

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