My Service Engine Soon light does not come on when the ignition is turned on and as a result I can't get the emissions test completed.
Does anyone know how to replace this light and what type of bulb is required?
It is a 2002 STS by the way.

Couple of things may be going on.

Either tha PCM cannot turn on the SES lamp. Or the IPC cannot see the SES 'on' command.

Or. The IPC SES lamp is burned out. In the IPC case, they are not bulbs, they are LED. That being said, the SES uses 2 LED's. So if both are out..somethings up. I have had to replace LED's indicators in my 2001.

GM also has a bulletin about the SES. It wont always lite up at start up.

Attached pic is of IPC SES LED's.


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