why does my Tesla Model S Original (2012-2020) battery die when the car is off

Tesla Model S Plaid/Refresh (2021-present)

Error Codes

1-3 hours

Time

medium

Difficulty

high

Severity

3 min read

538 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix battery drain issues in Tesla Model S (2012-2020). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Electrical

Estimated Time

1-3 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the main battery before working on electrical systems.
•Allow the vehicle to cool down before servicing to avoid burns.

Symptoms

•Battery drains rapidly when the vehicle is off
•"Battery Management System" warning displayed on the dashboard
•Vehicle fails to start or power on after being parked
•Reduced range when the vehicle is operational
•Unresponsive electronics when attempting to start

Diagnostic Steps

1
Scan the vehicle's systems using a Tesla diagnostic tool to check for error codes.
2
Inspect the battery health status and state of charge through the Tesla app or display.
3
Check for any parasitic draw by measuring the current draw from the battery when the vehicle is off.
4
Review recent software updates or changes that may have affected battery management.
5
Examine the 12V battery condition, as it may be contributing to the issue.
6
Inspect all electrical components and accessories for any signs of malfunction or continuous draw.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Multimeter
•Socket set
•Tesla diagnostic tool

Parts Required

•12V battery

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan the vehicle's systems using a Tesla diagnostic tool to check for error codes.
2
Inspect the battery health status and state of charge through the Tesla app or display.
3
Check for any parasitic draw by measuring the current draw from the battery when the vehicle is off.
4
Review recent software updates or changes that may have affected battery management.
5
Examine the 12V battery condition, as it may be contributing to the issue.
6
Inspect all electrical components and accessories for any signs of malfunction or continuous draw.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a flat surface and turned off.
Disconnect the vehicle from any charging source.

2. Inspect the 12V Battery

Tools Required: Multimeter, socket set
Check the voltage of the 12V battery using a multimeter.
- If voltage is below 12.4V, replace the battery.
If necessary, disconnect the negative terminal and replace with a new 12V battery that meets Tesla specifications.

3. Check for Parasitic Draw

Tools Required: Multimeter
Disconnect the negative terminal of the main battery.
Connect the multimeter in series between the negative terminal and the battery cable.
Measure the current draw; it should be below 50 mA.
- If it's higher, start pulling fuses one at a time to identify the circuit causing the draw.

4. Update Software

Tools Required: Tesla app or touchscreen
Ensure the vehicle is running the latest software version.
If not, connect to Wi-Fi and update the software, as updates may contain fixes for battery management issues.

5. Repair or Replace Faulty Components

After identifying any components causing parasitic draw, repair or replace them as needed.
Components may include the main battery contactors, fuses, or any aftermarket accessories installed.