HOSE 1361953 - Caterpillar

Use this procedure to troubleshoot any suspect problems with the following indicator lamps:
Low oil pressure lamp
High coolant temperature lamp
Low coolant level lamp
Maintenance indicator lamp
Warning lamp
Diagnostic lamp
Overspeed lamp
Backup ECM ready lamp
Backup ECM active lampThe indicator lamps are activated by the Electronic Control Module (ECM) in order to inform the operator of various engine conditions. When the keyswitch is placed in the ON position, the diagnostic lamp and the warning lamp are illuminated by the ECM for a brief period. The ECM provides high side drivers and low side drivers for the lamp outputs.The following lamps utilize a low side driver for the lamp output at the ECM:
Low oil pressure lamp
High coolant temperature lamp
Low coolant level lamp
Overspeed lamp
Backup ECM ready lamp
Backup ECM active lampThe following lamps utilize a high side driver for the lamp output at the ECM:
Maintenance indicator lamp
Warning lamp
Diagnostic lamp The most likely cause of a problem with an indicator lamp is the bulb. The next most likely cause is a problem with a wire or with a connector. The least cause is a problem with the ECM.Note: An override feature is available in Cat Electronic Technician (ET) for each of the lamp circuits. The override can be used to troubleshoot the lamp circuits.
Illustration 1 g01378744
Schematic for the engine's lamp circuits
Note: There are configuration parameters that are associated with the low coolant level lamp and the maintenance indicator lamp. Ensure that these parameters are configured correctly prior to troubleshooting the lamp circuits. Refer to Troubleshooting, "Configuration Parameters" for information that is related to the configuration of the lamp circuits.
Illustration 2 g01377328
Locations of the connectors that are associated with the lamp circuits (rear engine view)
(1) J1/P1 ECM connectors
(2) Customer connectors
Illustration 3 g01378791
Location of the connector for the engine mounted control panel (top view)
(3) Control panel connector
Illustration 4 g01367230
Terminal locations at the P1 ECM connector that are for the lamp circuits
(P1-12) Overspeed lamp
(P1-19) Diagnostic lamp
(P1-20) Warning lamp
(P1-21) Maintenance indicator lamp
(P1-28) Low oil pressure lamp
(P1-29) High coolant temperature lamp
(P1-30) Low coolant level lamp
Illustration 5 g01378839
Terminal locations at the P1 backup ECM connector that are for the lamp circuits
(P1-19) Diagnostic lamp
(P1-28) Backup ECM active lamp
(P1-29) Backup ECM ready lamp
Illustration 6 g01378844
Terminal locations at the customer connector that are for the lamp circuits
(Terminal 20) Low coolant level lamp
(Terminal 21) High coolant temperature lamp
(Terminal 22) Maintenance indicator lamp
(Terminal 23) Diagnostic lamp
(Terminal 24) Low oil pressure lamp
(Terminal 25) Warning lamp
(Terminal 27) Backup ECM active lamp
(Terminal 28) Backup ECM ready lamp
Illustration 7 g01389974
Terminal locations at the connector for the control panel that are for the lamp circuits
(Terminal 27) Backup ECM active lamp
(Terminal 28) Backup ECM ready lamp
(Terminal 26) Overspeed lamp
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Remove electrical power from the ECM.
B. Thoroughly inspect connectors (1), (2), and (3). Also, thoroughly inspect any of the other connectors that are associated with the lamp circuits. Refer to the Schematic of the engine for connector locations. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 45 N (10 lb) pull test on each of the wires for the lamp