mosseater wrote:
I suppose once a fault is triggered, it stays in the computer until cleared? Would that mean they'd be able to pinpoint the issue with the reader?
For regular check engine light codes, yes, but not necessarily true for transmission codes. My 2004 Ford Freestar van intermittently flashes the transmission fault light, and there is no stored code. Two different Ford dealers told me I need to bring it in when it is flashing and not wait until the next startup when it clears because the transmission codes are not stored. That is what the dealers both told me.