2025 (6th Gen) 4Runner Check Engine Light

[Administrator]

What It Means, When to Worry, and What to Do Next

(Reference: 2025 Owner’s Manual, pg. 576–577)
Link to Owners Manual: https://trail4runner.com/wp-content/uploads/2025/03/2025-4runner-owners-manual.pdf

The check engine light (MIL – Malfunction Indicator Lamp) is part of your 4Runner’s onboard diagnostics system. When it comes on, it means the vehicle’s computer has detected an issue with the engine, emission system, or powertrain components.

When the Light Comes On​

If the check engine light is illuminated but not flashing, it could be triggered by something minor such as:

• A loose or missing gas cap
• Temporary fuel mixture fluctuations
• Minor emissions irregularities
  In this case, check the gas cap first. Tighten it until it clicks, and the light may turn off after several trips.

If the light is flashing, it indicates a more serious condition such as engine misfire, which can cause immediate damage to the catalytic converter. In this case:

• Reduce speed and load
• Avoid hard acceleration or towing
• Drive to the nearest Toyota dealer for diagnosis

Immediate Steps​

1. Check if the gas cap is loose or damaged
2. Reduce load and avoid harsh driving
3. Observe engine performance and listen for unusual sounds
4. Visit a Toyota dealer or use an OBD2 scanner to retrieve diagnostic trouble codes (DTCs)

After Repairs​

Once the issue is resolved, the check engine light will typically turn off after a few driving cycles. If the problem persists or the light returns, further diagnosis may be required.

Maintenance Mode​

If the vehicle is being serviced, the check engine light may appear temporarily. Technicians can reset the warning using diagnostic tools once work is completed.

2025 4Runner Check Engine Light Diagram
Refer to pages 576–577 of the Owner’s Manual for light behavior descriptions, cause lists, and steps for initial troubleshooting.