Why is my check engine light not working?

If the dashboard light is good, then the ECM could be defective causing the light to not come on. Try removing a sensor harness and see if the light comes on. … If it does not, then check the computer for codes for the sensor you unplugged. If there is a code, and the MIL indicator says ON, then the light is burned out.

What causes a check engine light to not work?

It is possible that the ECU is damaged; however, it could be a simple problem like a damaged fuse, damaged electrical relay or problems with the dashboard itself. It’s best to have a professional mechanic to complete a check engine light inspection.

Can a check engine light be nothing?

Normally, the appearance of a check engine light indicates a problem somewhere in your vehicle, but nothing seems amiss. Your car is still running at its best and there seems to be absolutely nothing wrong. … It doesn’t have to take a mechanical issue in order for this light to appear.

How do I know if my check engine light is working?

Start with the engine off. Turn the key to “on,” and then run so that the engine cranks. Watch the dash during this time. The Check Engine Light should flash on, and stay on for a brief period.

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Why is my check engine light on but no codes?

Generally if the light is coming on and no codes are stored the processor that triggers the light is faulty or the circuit is shorted to power. disconnect that circuit from the ECU if the light goes off probably an issue with the ECU, if the light stays on look for a short to power on that circuit.

What to do if check engine light is on?

What to Do About the Check Engine Light

  1. Look for a serious problem that requires immediate attention. Check your dashboard gauges and lights for indications of low oil pressure or overheating. …
  2. Try tightening your gas cap. …
  3. Reduce speed and load. …
  4. Use built-in diagnostic services, if available.

Can AutoZone tell me why my check engine light is on?

Does AutoZone Scan Check Engine Lights? AutoZone does. If your light is on, and you are wondering why, head down to your local AutoZone where one of our store associates can help diagnose the issue through our free Fix Finder service.

How do I check my car for diagnostics?

Read the Car Code(s)

  1. Turn on the diagnostic tool. Basic tools should have a simple power button somewhere on the unit. …
  2. Access the diagnostic scanner. Some scanners will automatically start to read the car codes once powered on. …
  3. Record the data. …
  4. Optional: Clear the codes.