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

1-2 hours

Time

medium

Difficulty

high

Severity

3 min read

528 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 diagnostic procedures and repair instructions.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the high-voltage battery before working on electrical systems.
•Allow the vehicle to cool before inspecting components.

Symptoms

•Battery drain occurs after the vehicle is turned off.
•Vehicle fails to start due to insufficient battery power.
•Increased frequency of needing to recharge the battery.
•Possible alert messages or notifications on the vehicle's display regarding low battery.
•Power loss to auxiliary systems (e.g., lights, infotainment).

Diagnostic Steps

1
Check Battery Health: Use the Tesla app or an OBD-II scanner to check the battery's state of health and state of charge.
2
Inspect for Parasitic Drain: Measure the current draw from the battery with a multimeter while the vehicle is off.
3
Review Settings and Features: Check for any settings that may keep systems active (like Sentry Mode, Cabin Overheat Protection, etc.).
4
Examine 12V Battery: Inspect the 12V battery and its connections for corrosion or damage.
5
Perform Software Updates: Ensure the vehicle’s software is up to date, as updates may fix battery management issues.
6
Check for Faulty Modules: Investigate if any modules (like the infotainment system or climate control) are malfunctioning or remaining active when the car is off.

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
•OBD-II scanner

Parts Required

•New 12V battery
•Any necessary fuses or connectors (if damaged)

Related Faults

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Symptoms

•Battery drain occurs after the vehicle is turned off.

•Vehicle fails to start due to insufficient battery power.

•Increased frequency of needing to recharge the battery.

•Possible alert messages or notifications on the vehicle's display regarding low battery.

•Power loss to auxiliary systems (e.g., lights, infotainment).

Diagnostic Steps

1
Check Battery Health: Use the Tesla app or an OBD-II scanner to check the battery's state of health and state of charge.
2
Inspect for Parasitic Drain: Measure the current draw from the battery with a multimeter while the vehicle is off.
3
Review Settings and Features: Check for any settings that may keep systems active (like Sentry Mode, Cabin Overheat Protection, etc.).
4
Examine 12V Battery: Inspect the 12V battery and its connections for corrosion or damage.
5
Perform Software Updates: Ensure the vehicle’s software is up to date, as updates may fix battery management issues.
6
Check for Faulty Modules: Investigate if any modules (like the infotainment system or climate control) are malfunctioning or remaining active when the car is off.

Solution

1. Preparation

Ensure the vehicle is parked on a level surface and turned off completely.
Gather tools: multimeter, socket set, and OBD-II scanner.

2. Check and Replace 12V Battery

Sub-steps:
1. Open the rear trunk and locate the 12V battery compartment.
2. Disconnect the negative terminal first, followed by the positive terminal.
3. Remove the old 12V battery from the compartment.
4. Install the new 12V battery in the compartment.
5. Reconnect the positive terminal first, followed by the negative terminal.
Tools Required: Socket set, multimeter.

3. Disable Non-Essential Features

Sub-steps:
1. Access the vehicle's settings through the touchscreen.
2. Disable features such as Sentry Mode and Cabin Overheat Protection if they are not needed.
3. Save changes and exit the settings menu.

4. Inspect and Repair Faulty Modules

Sub-steps:
1. Using the OBD-II scanner, check for any fault codes related to the vehicle modules.
2. Identify any modules that show persistent errors.
3. Replace or reset any faulty modules as necessary, following the manufacturer's specifications.
Tools Required: OBD-II scanner.