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Check Engine Light Did Not Come On Failed Smog Test

My car failed the smog test because my check engine light DID NOT come on. The check engine light does not come on when the car is started up, or if the key is turned on. It failed a smog test because the light did not come on, and the computer recognized the problem. Is this a computer problem in the car or something as simple as a light bulb?

Answer:

Hopefully the problem is a faulty check engine light bulb or led. Do you have trouble code P0650? P0650 indicates the engine control computer (ECC) sensed the check engine light circuit as having either too high, too low, or no voltage present. The ECC controls the check engine light by activating the ground circuit of the lamp. Simplest problem is a burned lamp/light. Other problems may include a MIL (malfunction indicator lamp; same as check engine light) wiring problem... possibly a short or open electrical condition, poor electrical connection at the bulb/cluster/PCM, and the more serious fault of a faulty ECC. If you have an advanced scan tool, you can use it to turn the MIL on and off manually to verify its operation. you should also check to see if your vehicle has a fuse dedicated to the check engine light. If it does, ensure the fuse is not blown. posted by SmogTips Support

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