C11, C13, C15, and C18 Industrial Engines Caterpillar

Sensor Signal (Analog, Passive) - Test

Usage:

C13 A5K

Use this procedure to troubleshoot the electrical system if a problem is suspected with the sensor. Also use this procedure if any one of the diagnostic codes in Table 1.

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Table 1
Diagnostic Codes Table
CDL Code and Description	Comments
110-3 Engine Coolant Temperature Sensor : Voltage Above Normal	The code is logged if the engine has been running for more than 7 minutes and an open circuit has been detected.
110-4 Engine Coolant Temperature Sensor : Voltage Below Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
172–3 Intake Manifold Air Temperature Sensor : Voltage Above Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
172-4 Intake Manifold Air Temperature Sensor : Voltage Below Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
174-3 Fuel Temperature Sensor : Voltage Above Normal	The code is logged. The ECM will flag the fuel temperature as invalid data and the fuel temperature is set to a default value of 40 °C (104 °F).
174-4 Fuel Temperature Sensor : Voltage Below Normal	The code is logged. The ECM will flag the fuel temperature as invalid data and the fuel temperature is set to a default value of 40 °C (104 °F).
3683-3 Auxiliary Temperature #2 : Voltage Above Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
3683-4 Auxiliary Temperature #2 : Voltage Below Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
1836-3 Auxiliary Temperature Sensor : Voltage Above Normal	The code is logged. The ECM will flag the temperature as invalid data and the temperature is set to a default value.
1836-4 Auxiliary Temperature Sensor : Voltage Below Normal	The code is logged. The ECM will flag the temperature as invalid data and the temperature is set to a default value.
3372-3 Engine Charge Air Cooler #1 Outlet Temperature Sensor : Voltage Above Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.
3372-4 Engine Charge Air Cooler #1 Outlet Temperature Sensor : Voltage Below Normal	The code is logged. The ECM detects voltage that is not in the acceptable range.

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Illustration 1	g06114590
Schematic for the passive analog sensors

Probable Causes

Codes
Short circuit
Open circuit
Wiring
EGR temperature sensor

Recommended Actions

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect to Cat^® Electronic Technician (ET). B. Turn the keyswitch to ON. C. Access the "Active Diagnostic Code" screen on Cat ET. Note: Wait at least 30 seconds in order for the diagnostic codes to become active. D. Look for -3 and/or -4 codes:	Codes	Result: A -3 diagnostic code is active. Proceed to Test Step 2. Result: A -4 diagnostic code is active. Proceed to Test Step 3. Result: For a diagnostic code that is logged but not currently active, proceed to Test Step 4.
2. Create a Short at the Sensor Connector A. Turn the keyswitch to OFF. B. Disconnect the suspect sensor. C. Install the jumper wire between terminal 1 (sensor signal) and terminal 2 (sensor return) at the sensor connector. D. Turn the keyswitch to ON. E. Monitor the diagnostic codes on Cat ET. Check for an active -4 diagnostic code for the suspect sensor. Note: Wait at least 30 seconds in order for the diagnostic codes to become active. F. Turn the keyswitch to OFF.	Short Circuit	Result: The -3 diagnostic code remains active for the suspect sensor. There is an open in the harness. Repair: Repair the wiring or replace the harness. Result: A -4 diagnostic code became active after creating the short at the sensor connector. The wiring is OK. Repair: Replace the sensor. If the problem is not resolved, proceed to Test Step 3.
3. Create an Open at the Suspect Sensor Connector A. Turn the keyswitch to OFF. B. Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code. C. Turn the keyswitch to ON. D. Monitor the diagnostic codes on Cat ET. Check for an active -3 diagnostic code for the suspect sensor. Note: Wait at least 30 seconds in order for the diagnostic codes to become active. Note: For a 110-3 code, start the engine and let the engine idle for 7 minutes. The engine must be running for at least 7 minutes in order for the diagnostic to run. E. Turn the keyswitch to OFF.	Open Circuit	Result: The -4 diagnostic code remains active for the suspect sensor. There is an open in the harness. Repair: Repair the wiring or replace the harness. Result: A -3 diagnostic code became active after disconnecting the sensor. The wiring is OK. Repair: Replace the sensor. If the problem is not resolved, proceed to Test Step 4.
4. Perform the Wiggle Test A. Turn the keyswitch to ON. B. Use Cat ET to run the "Wiggle Test". C. Slowly wiggle the wiring and the connectors between the P2 connector and the sensor. Slowly wiggle the wiring and the connectors between the P1 connector and the sensor. Pay particular attention to the wiring near each connector. Be sure to wiggle all the wiring. D. As you wiggle the wiring look for these problems. - Loose connectors or damaged connectors - Moisture on the connectors or the wiring - Damage that is caused by excessive heat - Damage that is caused by chafing - Improper routing of wiring - Damaged insulation	Wiggle Test	Result: The wiring failed the Wiggle Test. Repair: Repair the wiring or replace the wiring. Result: The wiring passed the Wiggle Test. Repair: The problem may be intermittent. Inspect the wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect". Repair: If the wiring looks OK, perform the following procedure. 1. Turn the keyswitch to OFF. 2. Disconnect the connectors. Carefully inspect the terminals for proper installation. Make sure that each terminal is clean and dry. 3. Insert a pin into each socket. Verify that each socket grips the pin firmly. Repair any problems. 4. Connect all connectors.

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).