Hi guys,

I recently did an auto to manual swap, which required me to swap out the intake manifold from an auto to manual one as well. The auto IACV has 3 wires, while the manual one has 2.
So I had the new IACV wired, and the ecu repinned appropriatly.
However, I am throwing a CEL with the code p1508 which is a IAC Valve Circuit Failure.

So what could the problem be? The symptoms I am experiencing is a very low idle, and if I rev and hold the motor and 1500 rpm, the rpm will bounce from 1500 to 1600 constantly.

I am thinking it is either a broken or clogged up IACV, or an improperly wired IACV. Seems more like an electrical problem, which leads me to believe that maybe the wires were soltered wrong, but wouldn't that cause the car to not start at all?

Thanks for all help. I hate electrical problems

 

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