My 99 1500 with 5.2, keeps showing code p0505, idles and runs fine. I've checked ohms between PCM & IAC plugs all under 5 ohms, no ohms between ground & IAC plug. Getting power at terminals 1 & 2. Pulled IAC turned key on no movement, Tried a new IAC no movement, so all signs pointed to PCM. Bought new PCM had it programmed to VIN, removed negative battery cable, installed PCM. Stealership wants $125 to troubleshoot! Last night removed both battery cables, hooked them back up, started it up getting same code! Anyone have this problem & what fixed it?
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