Knowledge base

How does the Check Engine Light feature work?

Customer Care Agent Customer Care Agent
  • Updated

When does the Check Engine Light (CEL) turn on?

The check engine light comes on when the vehicle’s engine control unit (ECU) detects a problem that may affect vehicle performance and emissions.

How do I know what’s wrong?

The ECU reports diagnostic trouble codes (DTC) that describe the issue detected. Automatic can read any generic codes and offer a description (if available).

What do I do when an issue is detected?

Minor issues, such as a loose gas cap, can easily be dealt with on your own. We can't advise on specific repair procedures for your vehicle, but the information Automatic can detect will help a qualified mechanic with their diagnostics.

What if my engine light is on, but there are no trouble codes?

Some trouble codes are proprietary to your vehicle’s manufacturer and might indicate a problem beyond Automatic's capabilities to read it. We advise to take your vehicle to a mechanic who specializes in your vehicle’s make in these cases.

What does reseting the check engine light do to my car?

The check engine light clears when Automatic resets the vehicle’s (ECU). Resetting the ECU doesn’t modify your vehicle’s computer system nor does it solve the underlying issue. If the problem persists, the light will turn back on. This process simply resets the ECU's diagnostic tests. 

PLEASE NOTEThis will make your vehicle temporarily ineligible for emissions tests.

How do I know if the problem is fixed?

It depends on the problem, but it may take 3-4 days of driving for your vehicle to perform the necessary tests and determine if the problem still exists.

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