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

The ECM detects the following conditions:

• The signal for the secondary engine speed/timing sensor is intermittent or lost.

System Response:

The engine may misfire or the engine may run rough during starting. The check engine lamp will not be illuminated for this code unless the code has been active for ten hours.

There should not be a noticeable change in engine response unless the signal for the primary engine speed/timing sensor is lost. The engine will shut down if both the signal for the primary engine speed/timing sensor and the signal for the secondary engine speed/timing sensor are lost.

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

Results:

• OK - STOP