LAMP GP-SIGNAL 1151716 - Caterpillar

System Operation
The Backup Engine Speed Sensor determines engine speed by magnetically detecting the teeth on the flywheel starter ring gear. The ECM will not try to start the engine (either energize the shutoff solenoid or move the BTM) until it senses an engine speed signal. Engine speed is determined by the frequency, not the voltage, of the engine speed sensor output signal. The output frequency should be between 0 and 5 kHz. The backup engine speed sensor is a passive type sensor and does not require supply voltage. This sensor provides signal to the engine hour meter, overspeed switch and the electronic control module. To troubleshoot the backup engine speed sensor functionality, the main speed sensor must be disconnected. The backup engine speed sensor is a passive type sensor and does not require supply voltage for operation.Schematic
Diagnostic Codes
Functional Test