SEL is on, codes say both knock sensors bad

[jfachatz]

On my 99 Q45t, I did some home grown repair work on a cracked driver's headlamp housing. In order to remove it I had to also remove the air filter box and some of the duct work heading back to the engine air intake. While moving these things out of the way I loosened a braided ground from the driver's side of the engine that ends in a white modular plastic connector bolted and connected to the driver's shock tower. During reassembly, i could not recall where the gold circle end of this wire needed to connect to at the engine end. I connected it to a metal support for the air duct. Within 2 days my SEL light came on with error codes for both bank's knock sensors being bad. Is it possible that my attaching the ground in the wrong place on the engine could fool the ECU into thinking the knock sensors are bad or am I just dreaming and I need to prepare to replace both knock sensors? Thank you! -Jason

[jfachatz]

Thanks for the advice! Oh wait, I didn't get any. : ( I mean, I know I am a newb, but if I did something wrong like post in the wrong place at least give a person a break and let them know.

[dfddfd2]

Yes, absolutely, a bad ground throws everything out of whack (engineering term). Bolt the ground to the intake manifold, head or block.

[jfachatz]

Thank You dfddfd2! I connected the ground to where several other grounds connect (at a bracket that connects to the intake). They look like grounds for the ignition system in a bundle of wires running in front of the intake and under the engine cover. I know grounds can be picky, but the question remains if they are picky enough to care where I connected. I did find the proper location to connect it, but am only guessing that moving it will help. The location is below an A/C or power steering hose-the bolt comes in from below. It felt like it screws in to the driver's exhaust manifold.

Please, let me know if you think this will have an affect. Thank you so much!