COVER AS 4673390 - Caterpillar

The primary engine speed signal cannot be detected. The timing gear pattern returns within one second before being lost and the battery voltage is greater than 9 VDC for the last two seconds. The code is logged only if the engine has been running for three seconds. The code will be active and logged if the Electronic Control Module (ECM) detects an incorrect signal for one second. The battery voltage is greater than 9 VDC for the last two seconds.System Response:The code is logged. On engines with a secondary engine speed/timing sensor, the secondary engine speed/timing signal will be used if the primary engine speed/timing signal is lost.Test Step 1. Perform the following diagnostic procedure: "Engine Speed/Timing Sensor"Results:
OK - STOP
REPAIRED, OK - STOP