PIN 5508164 - Caterpillar

Asphalt Paver:
AP-1000D (S/N: EAD1-UP)
AP-1055D (S/N: FAC1-UP; A6P1-UP)
AP600D (S/N: TFM1-UP; TFZ1-UP)
AP655D (S/N: GNN1-UP; MAN1-UP; MAT1-UP; GNZ1-UP)
The 220-0230 Alarm As (BACKUP) makes a low decibel noise when the engine key start switch is in the ON position and engine off. This noise is often misunderstood as a failure of the backup alarm or indicating a sensor is in neutral. The noise is due to a small current that is supplied to the alarm in order to diagnose an open or short circuit. The small current causes a low decibel noise that is similar to a cracking sound that is noticeable when the engine is off and the engine key start switch is in the ON position.Do not attempt to repair the back up alarm. The low level noise is a diagnostic signal and this is normal.