my BMW 3 Series E90/E91 (2005-2012) remote start not working, what's wrong?

BMW 3 Series E90/E91 (2005-2012)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

538 words

Problem Statement

The remote start feature of a BMW 3 Series E90/E91 (2005-2012) is not functioning, indicating a potential issue with the remote key fob, battery, or the vehicle's remote start sys

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components to avoid short circuits.
•Ensure the engine is turned off and cool before inspecting the remote start system.

Symptoms

•Remote key fob not unlocking or starting the vehicle
•Remote start feature not responding when activated
•Doors may not lock or unlock via remote
•Check engine light may be illuminated
•Battery warning light on the dashboard

Diagnostic Steps

1
Check the battery in the remote key fob for voltage and replace if necessary.
2
Verify the vehicle's battery voltage to ensure it is charged and functional.
3
Scan the vehicle's onboard diagnostics using an OBD-II scanner for any related error codes.
4
Inspect the remote start system wiring and connections for any visible damage or corrosion.
5
Confirm that the vehicle is in the proper conditions for remote start (e.g., gear in park, hood closed).
6
Test the remote key fob functionality with another similar vehicle if available.

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

•OBD-II scanner
•Multimeter
•Flathead screwdriver
•Replacement battery (CR2032)

Parts Required

•Replacement battery for the key fob
•Vehicle battery (if needed)

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Diagnostic Steps

1
Check the battery in the remote key fob for voltage and replace if necessary.
2
Verify the vehicle's battery voltage to ensure it is charged and functional.
3
Scan the vehicle's onboard diagnostics using an OBD-II scanner for any related error codes.
4
Inspect the remote start system wiring and connections for any visible damage or corrosion.
5
Confirm that the vehicle is in the proper conditions for remote start (e.g., gear in park, hood closed).
6
Test the remote key fob functionality with another similar vehicle if available.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked in a safe, well-ventilated area.
Disconnect the vehicle's battery to ensure safety during any electrical work.

2. Replace Remote Key Fob Battery

Sub-steps:
1. Remove the key fob cover using a small flathead screwdriver.
2. Extract the old battery (typically a CR2032) and replace it with a new one, ensuring the correct polarity.
3. Reassemble the key fob and test the remote start function.

3. Check and Replace Vehicle Battery

Sub-steps:
1. Use a multimeter to check the voltage of the vehicle's battery; it should read around 12.6 volts or higher.
2. If voltage is low, charge the battery or replace it if it is old and unable to hold a charge.
3. Reconnect the battery terminals, ensuring they are secure.

4. Inspect Remote Start System

Sub-steps:
1. Locate the remote start module (if installed) under the dashboard.
2. Check all wiring and connectors for loose connections or signs of wear.
3. Repair or replace any damaged wiring or connectors.

5. Verify Vehicle Settings

Sub-steps:
1. Ensure the vehicle is in park and the hood is securely closed.
2. Check the owner's manual for any specific settings that may affect remote start functionality.