BOLT 1A1135 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the electrical power supply.This procedure covers the 168-02 System Voltage intermittent/erratic diagnostic code.This procedure tests whether the proper voltage is being supplied to the Electronic Control Module (ECM).Unswitched battery voltage is supplied to the ECM via the customer connector. The ECM receives the input from the keyswitch via the marine engine control panel and from a remote location. When the ECM detects battery voltage on the keyswitch circuit, the ECM will power up. When battery voltage is removed from the keyswitch circuit, the ECM will power down. The ECM requires the keyswitch to be in the ON position in order to maintain communications with the electronic service tool.Problems with the power supply to the ECM can occur on either the positive side or the negative side of the battery circuit.For intermittent problems such as intermittent shutdowns that could be caused by the engine wiring, temporarily bypassing the engine wiring may be an effective means of determining the root cause. A bypass harness is used to bypass the engine wiring. A means of bypassing the engine wiring is explained in this test procedure.
Illustration 1 g01129612
Schematic for the electrical power supplyTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01130307
Engine components for the electrical power supply (1) J61 customer connector (2) J1/P1 ECM connectors (3) J69 connector for the marine engine control panel (typical location)
Thoroughly inspect connectors (1), (2), and (3). Also inspect the connections for the battery and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01132902
P1 terminals that are associated with the electrical power supply (P1-48) +Battery (P1-52) +Battery (P1-53) +Battery (P1-61) −Battery (P1-63) −Battery (P1-65) −Battery (P1-67) −Battery (P1-70) Keyswitch
Illustration 4 g01136760
Terminals on the service tool connector that are associated with the electrical power supply (A) +Battery (B) −Battery
Illustration 5 g01130772
Terminals on the customer connectors that are associated with the electrical power supply (1) +Battery (2) −Battery (3) −Battery (5) +Battery (8) +Battery (9) −Battery (30) Keyswitch
Illustration 6 g01130782
Terminals on the connector for the marine engine control panel that are associated with the electrical power supply (3) Keyswitch (8) +Battery (10) −Battery
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the electrical power supply.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Also, check the harness and wiring for abrasions and for pinch points from the keyswitch to the ECM.Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the wiring and/or the connectors. Replace