SHIM 1W9391 - Caterpillar

Conditions Which Generate This Code:The Electronic Control Module (ECM) detects at least one of the following conditions:
The pattern of the timing ring is lost without a ramp down in engine speed.
The pattern of the timing ring returns within one second of being lost.
Battery voltage is less than 9 V for the last two seconds.ORThe ECM will log a diagnostic code, and the ECM will have an active diagnostic code if the ECM detects all of the following conditions:
There is an invalid pattern for the timing ring for one second.
The secondary engine speed/timing sensor has a valid pattern for the timing ring.
The secondary engine speed/timing sensor has a signal that is greater than 100 rpm.
Battery voltage is less than 9 V for the last two seconds.System Response:The ECM will log the diagnostic code. The ECM may have an active diagnostic code. The diagnostic code may be viewed on a display module or on the Caterpillar Electronic Technician (ET). 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 shutdownNote: The engine will shut down only if both the primary engine speed/timing sensor and the secondary engine speed/timing sensor fail.Test Step 1. Perform the following test: Engine Speed/Timing Sensor Circuit - TestResults:
OK - Stop.