Test Point 21 - Speed/Reference Sensor

Test Point 23 - Speed/Reference Sensor:

TEST POINT 23 SPEED/REFERENCE SENSOR
1. Disconnect DME control unit electrical connector under drivers seat.
2. Connect oscilloscope across harness terminals 47 and 48.
3. Crank engine and observe scope pattern.

Engine Speed Sensor Scope Pattern:

4. The scope pattern should be as shown and at least 3 volts peak to peak. If the pattern is correct but voltage low check sensor adjustment. Adjustments If pattern is incorrect or does not exist, continue.

Terminal Identification:

5. Recheck for pattern directly at sensor connector, terminals 1 and 2.
6. If pattern is now correct, repair wiring. If pattern still is not available or incorrect, replace sensor.