3406E, C-10, C-12, C-15, C-16 and C-18 On-highway Engines Caterpillar

The ECM detects the following conditions:

• The signal from the primary engine speed/timing sensor is intermittent or lost.

System Response:

The ECM will use the secondary engine speed/timing sensor to determine engine speed. The check engine lamp will not be illuminated for this code unless the code has been active for 10 hours.

There may be a slight change in engine response when the ECM is switched to the secondary engine speed/timing sensor.

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

Results:

• OK - STOP