Check Engine Light Not On But Codes Found

You ve only got two choices at this point.

Check engine light not on but codes found.

For example any problem that affects the emissions system will automatically light the check engine light. Press the erase clear button on your scanner then turn off the key and disconnect it. Everything in the obdii code list is in some way related to emissions. However all error codes are stored so you can look at historical data even with a 10 bluetooth obdii dongle and see what the code was before.

Most frequently the software errors stem from a low level obd reader being used. One main reason that a check engine light comes on with no code being stored is that there is a software error. So no codes when it was scanned. This is often the result of something being wrong with the obd reader that the driver parts store or mechanic shop is using.

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. Clearing any codes present will turn off your check engine light temporarily. If your check engine light is on but no code it s your scan tool not the vehicle. 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.

If the check engine light is on you ve got a trouble code stored. 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. I d guess that something happened which triggered the light but the condition didn t persist. The same is true if you have abs light on tcs light on vsc light on etc.

In that case you could scan the computer and find a code even though the light wasn t on.