C9.3 Engines for Caterpillar Built Machines Electrical Power Supply

Electrical Power Supply - Test

C9.3 Engines for Caterpillar Built Machines [KENR5393]

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ELECTRICAL AND STARTING SYSTEM

BATTERY GP

C9.3 Engines for Caterpillar Built Machines Electrical Power Supply - Test

System Operation Description:

Use this procedure to troubleshoot the electrical system if a problem is suspected with the power to the engine Electronic Control Module (ECM) or if any one of the diagnostic codes in Table 1 is active or easily repeated.

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Table 1
Diagnostic Codes Table
CDL Code	Code Description	Comments
168-2	Electrical System Voltage : Erratic, Intermittent, or Incorrect	The engine is running. The battery voltage falls below 6 VDC and the voltage returns above 9 VDC for three voltage readings in the last 7 seconds.
168-3	Electrical System Voltage : Voltage Above Normal	The ECM detects voltage that is above the acceptable value.
168-4	Electrical System Voltage : Voltage Below Normal	The ECM detects voltage that is below the acceptable value.
1834-2	Ignition Key Switch loss of signal	The ECM detects an erratic signal from the keyswitch. The keyswitch was cycled at least three times in the last second.

The engine ECM requires the keyswitch to be in the ON position in order to maintain communications with AVSpare Electronic Technician (ET).

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Illustration 1	g02100347
Schematic for the electrical power supply circuit

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for codes A. Establish communication between the Cat ET and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Start the engine. Run the engine until the engine is at normal operating temperature. C. Download the "Product Summary Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. Look for these codes: • 168-2 • 168-3 • 168-4 • 168-2	Codes	Result: A 168-2 or a 1834-2 diagnostic code is active. Proceed to Test Step 2. Result: A 168-3 diagnostic code is active. Proceed to Test Step 3. Result: A 168-4 diagnostic code is active. Proceed to Test Step 4.
2. Inspect the Electrical Connectors and the Wiring For the Charging Circuit A. Turn the keyswitch to the OFF position. B. Check the harness connections at the battery and at the alternator. C. Check the harness between the battery and the alternator.	Electrical Connectors	Result: The harness and connectors appear to be OK. Repair: There is a problem with the charging system. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting". STOP Result: The connectors and/or wiring are not OK. Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are coupled. Verify that the repair eliminates the problem. STOP
3. Check the Charging Circuit A. Check the operation of the charging circuit.	Battery Voltage	Result: The battery voltage is high. Repair: There is a problem with the charging system. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting". STOP
4. Check the Battery A. Turn the keyswitch to the ON position. Do not start the engine. a. Check the brightness of the lights. B. Turn the keyswitch to the ON position. Start the engine. b. Check the brightness of the lights.	Battery	Result: The lights are dim when the engine is not running. The lights are brighter when the engine is running. There is a problem with the battery. Proceed to Test Step 5. Result: The lights are dim when the engine is not running. The lights are still dim when the engine is running. Repair: There is a problem with the charging system. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting". STOP
5. Check the Battery Charge A. Measure the no-load battery voltage at the battery posts. B. Test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 V and 12 V Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure".	Battery Charger	Result: The batteries pass the load test. The measured voltage is between 11.0 VDC and 13.5 VDC for a 12 V system and between 22.0 VDC and 27.0 VDC for a 24 V system. Repair: Check the wiring between the batteries and the ECM. Repair the wiring and/or the connectors. Verify that the repair eliminates the problem. STOP Result: The battery voltage is low or the battery did not pass the load test. Repair: Recharge or replace the faulty batteries. Verify that the repair eliminates the problem. STOP

Test Step 1.

The procedure corrected the issue. Return to service.

Results:

The procedure did not correct the issue. -
Repair: Contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).

STOP