Q: Where are the crankshaft position sensor circuits A and B on a 2002 Oldsmobile Intrigue 3.5 L

There are two different crankshaft position sensors on your vehicle, one designated "A" and the other "B". Both of these sensors are mounted to the engine block. The two circuits that you are referring to run from the sensors (the circuit includes the sensor electrical component itself) through the vehicle wiring harness to the engine computer. If you are seeing an OBD-II trouble code, such as P0385, P0386, and so forth, that refers to these circuits ("A" versus "B"), the fault could be in the wiring to and from the sensor, the terminal connection at the sensor or any of these other possibilities: Damaged reluctor ring, such as missing teeth; The sensor output could be open; Damaged crankshaft position sensor connector; Sensor output shorted to voltage or ground; Failed crank sensor; Failed PCM (not typical); Damaged signal plate; and weak or dead battery. To determine the exact fault requires diagnostics. Crankshaft position sensors can be directly tested using an automotive scan tool and consequently you should not replace the sensor unless it is actually tested and properly condemned. Performing a diagnostic avoids needless repairs. If you suspect an issue with these sensors and/or want to schedule a diagnostic, the recommended service is a check engine light diagnostic. If you request that service, the responding certified mechanic will read the codes and then test actual parts, that is perform a diagnostic, to find the fault and get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.