Q: How to replace a camshaft sensor? Shows sensor "A" on diagnostic check 2002 Saturn SL1

Hello - there is no physical camshaft position sensor on this engine. This function is handled by the coil and ignition module. The error is likely a wiring problem, either with the plug wires, or the physical wiring to the ignition module (corrosion). Clean all wiring connections on the ignition side of the engine, remember to include dielectric grease to slow future corrosion, replace the plug wires if needed, and you should be good to go!