Check Engine Light Not On But Codes Found

If your check engine light is on but no code it s your scan tool not the vehicle.

Check engine light not on but codes found.

This is often the result of something being wrong with the obd reader that the driver parts store or mechanic shop is using. The same is true if you have abs light on tcs light on vsc light on etc. One main reason that a check engine light comes on with no code being stored is that there is a software error. Everything in the obdii code list is in some way related to emissions.

In that case you could scan the computer and find a code even though the light wasn t on. Press the erase clear button on your scanner then turn off the key and disconnect it. But if the problem is not emissions related and also not critical it may be stored in the computer but not light the check engine light. There are other cases where there s no check engine light but codes.

After pressing erase clear and waiting until you see a no codes message you can turn off your vehicle and disconnect the scanner. 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. Buy a scan tool that can read enhanced as well as b c and u codes or pay a shop to read the codes for you. If the check engine light is on you ve got a trouble code stored.

So no codes when it was scanned. You ve only got two choices at this point. 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. I d guess that something happened which triggered the light but the condition didn t persist.

For example any problem that affects the emissions system will automatically light the check engine light.