Hi, I have a small issue with my conversion. It's running 2003 Silverado 1MB PCM and TAC and will throw a P1518 code if the ignition key is cycled on, off and on quicker than 3 seconds. I believe the code is thrown due to the fact the TAC needs to power up a split second after the PCM. I have tried putting a load on the TAC supply to drain the power once the key is off but it made no difference. It appears the TAC is not powering off quick enough. I have the TAC 12v power wired as per the Silverado drawing, connected to the PCM Switched 12v supply. I am running COS V3. Just wondering if anyone else has seen this problem? I have tried a different PCM and no difference. Any info would be much appreciated.