TURBOCHARGER GROUP 9N0111 - Caterpillar

System Operation Description:Use this procedure under the following conditions:This procedure tests whether proper voltage is supplied by the wiring. Use this procedure if the diagnostic code is logged or active.
168-0 System Voltage High
168-1 System Voltage Low
168-2 System Voltage intermittentAlso, use this procedure if you suspect that the ECM is not receiving the battery supply voltage.Note: This code can be generated by rapidly cycling the keyswitch. If this occurs, clear the logged diagnostic codes in order to prevent future confusion or an incorrect diagnosis.The following background information is related to this procedure:The ECM receives electrical power (battery voltage) through the wiring that is supplied by the engine harness. The ECM input at connector P1:23 (Switched +Battery) receives battery voltage from the keyswitch when the keyswitch is in the ON position or the START position. When the ECM detects battery voltage at this input, the ECM will power up. When battery voltage is removed from this input, the ECM will power down.The cause of an intermittent power supply to the ECM can occur on either the positive side or the negative side of the battery circuit. Both sides are routed from the ECM to the battery. The three connections for the unswitched +battery should be routed through a dedicated protective device (circuit breaker).The engine ECM requires the keyswitch to be in the ON position in order to maintain communications.For intermittent problems such as intermittent shutdowns that could be caused by engine wiring, temporarily bypassing the engine wiring may be an effective means of determining the root cause. If the symptoms disappear with the bypass wiring, the engine wiring is the cause of the problem. A means of bypassing engine wiring is explained in this test procedure.Note: Refer to the Electrical Schematic for proper wiring information.Test Step 1. Inspect Electrical Connectors And Wiring
Illustration 1 g00885754
P1 ECM connector
Thoroughly inspect the harness connector J1/P1 and the Customer Connector J3/P3. Also inspect the connections for the battery and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the following connections:
P1:4 and P1:6 (Unswitched positive battery)
P1:5 and P1:11 (Negative battery)
P1:23 (Switched positive battery)
P1:14 (Remote Shutdown Switch)
Check the ECM connector (allen head screw) for the proper torque of 2.25 N m (20 lb in).
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 connectors, pins, and sockets should be completely coupled and/or inserted. The harness and wiring should be free of corrosion, abrasion, and/or pinch points.Results:
OK - All connectors and wiring is proper. Proceed to Test Step 2.
Not OK - There is a problem with the connectors or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are