Periodic epc light, but no fault code?

[flanagaj]

I replaced the head on the Polo on Sunday and now it's running great. Compression is where it should be across all cylinders and the spark plugs are a nice colour too indicating it's running well. Before I started the head my daughter did say the EPC would come on but make no difference to the performance of the car. So I have been driving the car for 2 days and all was fine, but after ~ 70 miles of use the EPC came on. I have just gone out and plugged my KZYEE OBD II fault code reader in and it says there are no faults. I started the car and the EPC light has gone off.

Anyone have any ideas as I want to try and understand what might be causing this and whether it was responsible for the head going last time within 5 months?

Thanks

[Bepis]

I don't see it being an issue with the head as that was mechanical work and the EPC light indicates an issue with the Electronic Power Control. However, you mentioned that there are no faults and the car seems to drive fine which is odd as most EPC issues seem to be a dodgy throttle body connection accompanied by erratic revving as seen here:

https://youtu.be/nPE0NM_VOg4?t=12

I did find this after a quick google though:

"EPC stands for electronic power control, and the light is seen when there is a fault with the throttle body, traction control, throttle pedal, or cruise control systems."

If it drives fine I can't see it being an issue with the throttle body or throttle pedal but it's probably worth a look to eliminate them.

I imagine you had to disconnect the throttle body to take the head off so I would start there and see if there are any loose connections or frayed wires and if the throttle plate opens and closes fully.

Hope that helps

[RUM4MO]

Things would be a lot simpler if you had access to some thing like VCDS as you would be able to check all controllers for all/any VW Group extended ranges of fault codes, and also perform "basic settings" on the throttle body.