how to troubleshoot the CAN bus communication error on my Tesla Outback 5th Generation (2015-2019)

Subaru Outback 5th Generation (2015-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

3 min read

536 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 troubleshoot CAN bus communication errors in Tesla Outback 5th Generation (2015-2019). Step-by-step guide with diagnostic and repair instructions.

Affected Component

Electrical

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems to prevent shock or short circuits.
•Ensure the vehicle is off and cool before inspecting or repairing components.

Symptoms

•Check engine light illuminated
•Malfunction indicator lights on the dashboard
•Erratic behavior of electronic features (e.g., windows, locks)
•Loss of communication with diagnostic tools
•Reduced engine performance or stalling
•Inconsistent readings from the speedometer or fuel gauge

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific CAN bus-related errors.
2
Visually inspect the CAN bus wiring harness for any signs of damage, corrosion, or loose connections.
3
Check the battery voltage and ground connections to ensure the electrical system is functioning properly.
4
Use a multimeter to test the resistance of the CAN bus wires; it should be within manufacturer specifications.
5
Inspect the CAN bus termination resistors to verify they are present and functioning correctly.
6
Review the vehicle's service history for any recent repairs that may have affected the CAN bus system.

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
•Wire cutter/stripper
•Socket set
•Screwdriver

Parts Required

•CAN bus termination resistors (if replacement is necessary)
•Electrical tape or heat shrink tubing (for wiring repairs)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific CAN bus-related errors.
2
Visually inspect the CAN bus wiring harness for any signs of damage, corrosion, or loose connections.
3
Check the battery voltage and ground connections to ensure the electrical system is functioning properly.
4
Use a multimeter to test the resistance of the CAN bus wires; it should be within manufacturer specifications.
5
Inspect the CAN bus termination resistors to verify they are present and functioning correctly.
6
Review the vehicle's service history for any recent repairs that may have affected the CAN bus system.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a level surface and the ignition is off.
Disconnect the battery to avoid electrical shorts.

2. Inspect Wiring

Remove the underdash panel to access the CAN bus wiring.
Check for frayed wires, corrosion, or physical damage along the harness.
Repair or replace damaged sections using appropriate automotive wiring techniques.
- Tools Required: Wire cutter/stripper, electrical tape, soldering iron (if needed).

3. Test CAN Bus Connections

Reconnect the battery and power the vehicle.
Use a multimeter to test the voltage levels on the CAN High (CANH) and CAN Low (CANL) wires; they should read approximately 2.5 volts at rest.
If readings are incorrect, repair or replace the faulty wiring or connectors.

4. Replace Termination Resistors

Locate and remove the CAN bus termination resistors at each end of the bus.
Inspect for damage; replace if necessary with OEM specifications (typically 120 ohms).
- Tools Required: Socket set, screwdriver.

5. Reassemble and Test

Reassemble any removed panels.
Reconnect the battery and perform a test drive to monitor for error codes and ensure all systems are functioning properly.