my Toyota Highlander makes a knocking noise when I accelerate what could be wrong

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

529 words

Problem Statement

Learn how to diagnose and fix knocking noise during acceleration in Toyota Highlander. Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow engine to cool before starting.
•Ensure the vehicle is securely raised on jack stands if working underneath.
•Ensure the vehicle is securely supported.

Symptoms

•Knocking noise when accelerating
•Possible vibration felt in the vehicle
•Decreased acceleration performance
•Engine misfires or rough running
•Unusual smells (e.g., burning oil or fuel)

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any engine-related issues.
2
Inspect the engine oil level and condition; look for signs of contamination or low levels.
3
Check the transmission fluid level and condition for any signs of burning or contamination.
4
Inspect the engine and transmission mounts for wear or damage.
5
Perform a visual inspection of the drivetrain components, including CV joints and axles.
6
Test drive the vehicle to replicate the knocking noise while listening for the source.

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
•Oil filter wrench
•Socket set
•Oil catch pan
•Transmission fluid pump
•Torque wrench

Parts Required

•Engine oil
•Oil filter
•Transmission fluid
•Engine/transmission mounts (if needed)
•CV joints or axles (if needed)

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any engine-related issues.
2
Inspect the engine oil level and condition; look for signs of contamination or low levels.
3
Check the transmission fluid level and condition for any signs of burning or contamination.
4
Inspect the engine and transmission mounts for wear or damage.
5
Perform a visual inspection of the drivetrain components, including CV joints and axles.
6
Test drive the vehicle to replicate the knocking noise while listening for the source.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a level surface and the engine is turned off.
Disconnect the battery to ensure safety during repairs.

2. Inspect Engine Oil

Remove the engine oil dipstick and check the oil level.
If low, add the correct type of oil as specified in the owner’s manual.
If dirty or contaminated, proceed to change the oil and filter.
- Tools Required: Oil filter wrench, socket set, oil catch pan
- Safety Warnings: Allow engine to cool before starting.

3. Check Transmission Fluid

Remove the transmission dipstick and check the fluid level and condition.
If low, add the recommended transmission fluid.
If fluid is burnt or contaminated, perform a transmission fluid change.
- Tools Required: Transmission fluid pump, socket set
- Safety Warnings: Ensure the vehicle is securely raised on jack stands if working underneath.

4. Inspect Engine and Transmission Mounts

Visually inspect the engine and transmission mounts for cracks or excessive wear.
If damaged, replace the mounts.
- Tools Required: Socket set, pry bar
- Safety Warnings: Ensure the vehicle is securely supported.

5. Examine Drivetrain Components

Check CV joints, axles, and other drivetrain components for excessive play or damage.
Replace any worn or damaged components as necessary.
- Tools Required: Socket set, torque wrench
- Safety Warnings: Ensure the vehicle is on a level surface.