COVER AS-PRECLEANER 2S2493 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the engine speed/timing sensor or if one of the diagnostic codes in Table 1 is active.
Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
190-2 Engine Speed Sensor erratic, intermittent, or incorrect The 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 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. The secondary engine speed/timing signal will be used if the primary engine speed/timing signal is lost. The code is logged.
190-3 Engine Speed Sensor voltage above normal A wire on the engine speed/timing sensor is disconnected and/or broken. There is a short circuit to the +Battery terminal. The secondary engine speed/timing signal will be used if the primary engine speed/timing signal is lost. The code is logged.
190-7 Engine Speed Sensor not responding properly The primary engine speed/timing sensor is connected to the harness for the secondary engine speed/timing sensor. The code is active.
190-8 Engine Speed Sensor abnormal frequency, pulse width, or period The engine speed is greater than zero rpm and the pattern from the timing ring is incorrect for five seconds. The secondary engine speed/timing signal will be used if the primary engine speed/timing signal is lost.
The code is logged if the pattern from the timing ring returns for five seconds.
342-2 Secondary Engine Speed Sensor erratic, intermittent, or incorrect The 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 will be active and logged if the ECM detects an incorrect signal for one second. The battery voltage is greater than 9 VDC for the last two seconds. The primary engine speed/timing signal will be used if the secondary engine speed/timing signal is lost. The code is logged.
342-3 Secondary Engine Speed Sensor voltage above normal A wire on the engine speed/timing sensor is disconnected and/or broken. There is a short circuit to the +Battery terminal. The primary engine speed/timing signal will be used if the secondary engine speed/timing signal is lost. The code is logged.
342-7 Secondary Engine Speed Sensor not responding properly The secondary engine speed/timing sensor is connected to the harness for the primary engine speed/timing sensor. The code is active.
342-8 Secondary Engine Speed Sensor abnormal frequency, pulse width, or period The engine speed is greater than zero rpm and the pattern from the timing ring is incorrect for five seconds. The primary engine speed/timing signal will be used if the secondary engine speed/timing signal is lost.
The code is logged if the pattern from the timing ring returns for five seconds. The ECM provides the engine speed/timing sensors