COVER ASSEM. 8N0267 - Caterpillar

Table 1
Graphical Display (MID 53)
DTC Code Description Comments
168-03 Electrical System Voltage: Voltage Above Normal The ECM activates this diagnostic code when the system voltage is above normal operating range.
168-04 Electrical System Voltage: Voltage Below Normal The ECM activates this diagnostic code when the system voltage is below normal operating range. Possible FMI 03 causes are:
Failed voltage regulator
Failed ECMPossible FMI 04 causes are:
Voltage remains low for an extended time after the engine is started.
Open circuit on one or more wires between the battery and ECM.
Open circuit on one or more wires providing ECM ground.
Battery disconnected with the key ON and the engine not running.
Failed ECM.
Illustration 1 g06233089Reference: Refer to the machine schematic.Complete the procedure in the order in which the steps are listed.
Table 2
Troubleshooting Test Steps Value Results
1. Identify Active Code Associated With The Circuit Voltage
A. Connect Cat Electronic Technician (Cat ET) Service Tool.
B. Check for codes.
No code present. OK - Code is not present.
STOP.
Not OK - Code is present.
Go to Step 2.
2. Check Connections And Harness.
A. Inspect the circuit harness connectors(1).
B. Inspect the harness.
Connectors are:
* Clean
* Secure
* In good condition
Harness is not:
* Kinked
* Chaffed OK - Connections and harness are good.
FMI 3 diagnostic code, go to Step 3.
FMI 4 diagnostic code, go to Step 4.
Not OK - A connection problem exists.
A. Clean and secure connectors(1).
B. Verify that the problem is corrected.
STOP.
Begin FMI 03 Troubleshooting Here.
3. Check The System Voltage At The ECM
A. Turn start switch and disconnect switch ON.
B. At the ECM harness connector, insert one 7X-1710 Multimeter Probe along the power contact.
C. At the ECM harness connector, insert one 7X-1710 Multimeter Probe along the return contact.
D. Observe the voltage measurement while wiggling the connectors and wires.
Voltage is:
≥ 21.5 VDC
< 24.8 VDC OK - Voltage is correct.
Go to Step 5.
NOT OK - Voltage is ≥ 24.8 VDC.
Repair: Repair charging system(2).
STOP.
Begin FMI 04 Troubleshooting Here.
4. Check The System Voltage At The ECM
A. Turn start switch and disconnect switch ON.
B. At the ECM harness connector, insert one 7X-1710 Multimeter Probe along the power contact.
C. At the ECM harness connector, insert one 7X-1710 Multimeter Probe along the return contact.
D. Observe the voltage measurement while wiggling the connections and wires.
Voltage is:
≥ 21.5 VDC
< 24.8 VDC Result: Voltage is correct.
Go to Step 5.
Not OK - Voltage is < 21.5 VDC.
Repair: Repair charging system.
STOP.
5. Recheck Connections And Code
A. Perform a 45 N (10 lb) pull test on each power supply circuit wire.
B. Reconnect all harness connectors.
C. Verify that all connectors are fully seated.
D. Verify that all clips are fastened securely.
E. Turn key start switch and disconnect switch ON.
F. Clear all diagnostic codes.
G. Operate the machine.
H. Stop machine.
I. Engage safety lock lever.
J. Check the diagnostic code with Cat ET.
Code is not active. OK - Diagnostic code is not active.
Initial diagnostic code may have been caused by poor connection.
Resume machine operation.
STOP.
Not OK - Diagnostic code is active.
Repair:
A. Recheck the circuit.
B. Perform this procedure again.
C. If the diagnostic code remains, contact your Technical Communicator.
(1) See Testing and Adjusting, "Electrical Connector - Inspect.
(2) See Special Instruction, REHS0354,