RPM Signal
WARNING: This page is about a different car, the 1993 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.
Crankshaft position and engine RPM are detected by pick-up coils in the distributor. The Engine Control Module (ECM) uses input signal for controlling Pulsed Secondary Air Injection (PAIR) system (if equipped), fuel injection system, ignition timing (spark advance), idle speed control system, fuel pressure control system (if equipped), EGR system, A/C-cut control system (if equipped) and heated oxygen sensor system (if equipped).
Crankshaft position input signal is delivered to G, G+ or G1 (and G2 on some models) terminal of ECM, and engine RPM input signal is delivered to NE or NE+ terminal of ECM.