3408E and 3412E Engines for Caterpillar Built Machines Caterpillar

The Electronic Control Module (ECM) will log a diagnostic code if the ECM detects all of the following conditions:

• The engine speed is greater than 0 rpm.

• The pattern for the timing ring is incorrect for five seconds.

Note: If The pattern for the timing ring is correct again for five seconds the diagnostic code deactivates.

System Response:

The ECM will log the diagnostic code. If a valid signal is not received from the primary engine speed/timing sensor, the ECM will default to the secondary engine speed/timing sensor.

• Engine misfires

• Engine shutdown

Note: The engine will shut down only if the signals from the primary engine speed/timing sensor and from the secondary engine speed/timing sensor are abnormal.

Test Step 1. Perform the following diagnostic procedure: Engine Speed/Timing Sensor Circuit - Test

Results:

• OK - STOP