C11, C13, C15, and C18 Industrial Engines Caterpillar

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

Table 1

Diagnostic Trouble Codes
CDL Code and Description	Comments
111–2 Engine Coolant Level Sensor : 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.
1834-2 Ignition Key Switch loss of signal	The ECM detects an erratic signal from the keyswitch because the keyswitch was cycled at least three times in the last second
168-0 Electrical System Voltage : Voltage Above Normal	The ECM detects voltage that is above the acceptable value.
168-1 Electrical System Voltage : Voltage Below Normal	The ECM detects voltage that is below the acceptable value.
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.

Illustration 1	g02154189

Probable Causes

• Codes

• Electrical connectors

• Wiring

• Charging circuit

• Battery charge

Recommended Actions

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Establish communication between the Cat® Electronic Technician (ET) and the ECM. B. Start the engine. Run the engine until the engine is at normal operating temperature. C. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. Check for the codes listed below: · 168-2 · 168-0 · 168-1 · 1834-2	Codes	Result: A 168-2 or a 1834-2 diagnostic code is active. Proceed to Test Step 2. Result: A 168-0 diagnostic code is active. Proceed to Test Step 3. Result: A 168-1 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 OFF. B. Check the harness connections at the battery and at the alternator. C. Check the harness between the battery and the alternator.	Connectors and Wiring	Result: The harness and connectors are OK. There is a problem with the charging system. Repair: Refer to Special Instruction, REHS0354, "Charging System Troubleshooting". Result: The connectors and/or wiring are not OK. Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all the seals are properly in place and ensure that the connectors are coupled. Verify that the repair eliminates the problem. If the problem is not resolved, proceed to Test Step 3.
3. Check the Charging Circuit A. Check the charging circuit. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting".	Charging Circuit	Result: The charging system is OK. Proceed to Test Step 4. Result: The charging system is not OK. Repair: Refer to Special Instruction, REHS0354, "Charging System Troubleshooting". If the problem is not resolved, proceed to Test Step 4.
4. Check the Battery Charge A. Measure the no-load battery voltage at the battery posts. B. Load-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 Charge	Result: The batteries are OK. Repair: 1. Verify that the "System Operating Voltage Configuration" is correctly configured in the engine ECM configuration parameters. 2. Check the connectors between the batteries and the ECM for moisture and/or corrosion. 3. Check the wiring between the batteries and the ECM. 4. Repair the wiring and/or the connectors. Result: The battery voltage is NOT OK. Repair: Recharge or replace the faulty batteries.

If the problem is not resolved, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).