ADAPTER 3G8354 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the electrical power supply.This procedure covers the following diagnostic codes:
168-00 System Voltage High
168-01 System Voltage Low
168-02 System Voltage intermittent/erraticThis procedure tests whether proper voltage is being supplied to the Electronic Control Module (ECM).The Electronic Modular Control Panel (EMCP) controls the +Battery voltage to the Electronic Control Module (ECM) through a series of relays and two emergency stop switches. Voltage to the keyswitch input is provided to the ECM through one of these relays. The −Battery is supplied to the ECM through a battery isolator switch (option) that is used to manually remove the battery power from all electrical components.Voltage from the keyswitch is supplied at keyswitch input P1-70 of the ECM. A control circuit from the EMCP (fuel control relay) is used to actuate the control relay. The output from the control relay provides voltage to the keyswitch input of the ECM.The +Battery voltage is supplied to inputs P1-48, P1-52, and P1-53 of the ECM. Activation of the control relay provides the control signal to the start relay. The start relay provides +Battery voltage to the ECM.The negative battery is supplied to inputs P1-61, P1-63, and P1-65 of the ECM.Both the control relay and the start relay must be actuated in order for the ECM to be fully powered. Circuit protection is provided by a circuit breaker for the start relay and a fuse for the control relay.
Illustration 1 g01199826
Schematic for the electrical power supply (typical example)
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the EMCP.
Turn the battery isolator switch to the OFF position.
Illustration 2 g01186024
Location of the J1/P1 ECM connectors (typical left side engine view)
Thoroughly inspect the J1/P1 ECM connector. Inspect all of the connectors that are associated with the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01240939
P1 ECM connector
(P1-48) +Battery
(P1-52) +Battery
(P1-53) +Battery
(P1-61) −Battery
(P1-63) −Battery
(P1-65) −Battery
(P1-70) Keyswitch
Illustration 4 g01200187
Location of the connector for the EMCP (typical view of the rear of the panel)
(48) Fuel control relay (output)
(58) Fuel control relay (input)
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors and the connector for the EMCP that are associated with the circuit.
Check the torque of the allen head screws for the ECM connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from the batteries to the ECM. Expected Result:All 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 connectors and wiring 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 parts, if necessary. Verify that the original problem has been resolved.STOPTest Step 2. Check the Voltage to the ECM
Disconnect the connector from the rear of the EMCP.
Use