Engine Light comes on while idleing

[fitz_vt]

gday guys,
today i wash washing my car in prep for the cruise tonight lol.... and i was waiting at the car wash and my engine light came on, no rough idle is just came on..... it also happened while at a mates house .... it only happens on idle.

[JacksonVX2]

Check the plugs on the TPS and Idle Control Valves to see if they have come loose. They are located on the entry point of the Air intake just as it enters into the manifold. If not, it could possibly be your oxygen sensor. Either way take it to holden to have the computer plugged in. Its obviously logged a fault code.

[VTCommoDude]

The same is with mine. My car kept stalling, was hard to start sometimes and stalled sometimes.
I changed leads and plugs, fully cleaned out the throttle body, surrounding TB and air sensors, cleaned IAC and EGR valves, and it has just been serviced. Checked the error codes - 12: nothing wrong.
Got in my car and it starts perfectly again, it also powers along like a new car on pills, but the engine light still comes on randonly. It runs OK, then suddenly misses and the light comes on. Error 12 means nothing is wrong with sensors etc.
If you figure it out, please let me know.