What would cause the SES light to come on after installing a 15% pulley and colder plugs? The dealer says it is faulting due to improper crankcase pressure. I've got a HAI and a zip-tied bypass valve, but those mods have been in place for months.

The SES light came on a couple days after installing the pulley. It went out once on it's own, and once when the dealer cleared it, and both times came back on under heavy acceleration.

I'm going to put the bypass valve and HAI back to stock to see if that helps, but I'm not optimistic.

 

What was the error code (DTC)?

 

I don't know the specific error code, but the dealer said it was caused by bad crankcase pressure. Would having the specifc code help?

 

The zip-tied BPV can definitely cause a fault because the upstream pressure is lower than it should be. Cut that zip tie and hook up a VGS.

Still fault-free 2 months later. :smile:

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Thanks, I'll try that.

 

Undoing the zip tie fixed the SES on the way to the parts store, but the yo-yo is back. I'll get the VGS in later today and see what happens.