Engine Speed Sensor: Testing and Inspection

CIS Turbo ECU Harness Connector (Pin # Locations):

STATIC TEST

Engine Sensor Electrical Connectors:

1. Unplug harness connector from crank position sensor lead (gray connector on bracket near ignition coil).

2. Check resistance between terminals #1 and #2 of male connector.
- Resistance should be approx. 1K ohms. If not, replace sensor.

3. Check resistance between terminals #1 and #3, and between terminals #2 and #3 of male connector.
- Resistance should be infinite (no continuity). If there is any continuity (even if resistance is very high) replace sensor.

4. Check for open or grounded circuit between ECU terminals #29, #11, and #28, and sensor female harness connector terminals #1, #2, and #3 respectively, with ECU harness connector disconnected.

5. Check clearance between sensor tip and teeth of flywheel.
- Clearance should be 1.10mm (0.043").

6. Check for excess accumulation of metal shavings or other ferrous material on the sensor tip.

If no problems have been found, but a code 2111 was displayed, then there is a poor connection at the ECU or the ECU is faulty.

DYNAMIC TEST

Engine Speed Sensor Signal:

The engine speed sensor can be tested dynamically with the use of an oscilloscope. When the engine is running, the sensor will produce an alternating current wave pulse each time a flywheel tooth passes the sensor tip which, when viewed on a scope, approximates a sine wave. The wave pattern should look similar to that shown in the diagram, and can be observed on a scope by probing terminals #1 and #2 of the sensor connector (use appropriate break-out box or parallel connector test leads).
Many automotive oscilloscopes are designed only to display primary and secondary ignition patterns and are not able to perform this type of test. To find out if your scope has this capability, or for correct procedures on hooking up a scope see the manufacturers instructions for your particular scope.