C13 Industrial Engine Caterpillar

Switch Circuits - Test

Usage:

C13 JR9

Use the following procedure to troubleshoot a problem with a switch circuit. The procedure that follows also covers the diagnostic codes that are listed in Table 1.

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Table 1
Diagnostic Codes
J1939	Description	Comments
107-3	Engine Air Filter 1 Differential Pressure : Voltage Above Normal	This code indicates a fault in the circuit for the air filter restriction switch. The air filter restriction circuit is open or shorted for at least 1 second while the engine is not running. The open or short circuit depends on the configuration of the switch.

Tables 2 and 3 contains the normal engine conditions and switch states for the air filter restrictions switch.

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Table 2
Normally Open Air Filter Restriction Switch
Engine Condition	Switch State
Not running	Open
Running	Closed

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Table 3
Normally Closed Air Filter Restriction Switch
Engine Condition	Switch State
Not running	Closed
Running	Open

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Table 4
Troubleshooting Test Steps	Values	Results
1. Check the "Air Filter Restriction Switch Configuration". A. Turn the keyswitch to ON. B. Connect to Cat® Electronic Technician (ET). C. Under "Configuration Parameters" check the "Air Filter Restriction Switch Configuration".	Air Filter Restriction Switch Configuration	Results : The switch is configured to "Normally Open". Proceed to Test Step 2. Results : The switch is configured to "Normally Closed". Proceed to Test Step 3.
2. Check the Air Filter Restriction Switch A. Turn the keyswitch to OFF. B. Disconnect the air filter restriction switch from the wiring harness connector. C. Turn the keyswitch to ON. D. Monitor Cat ET for active fault codes.	Diagnostic codes	Results : There is not an active 107-3 fault code. A failed air filter restriction switch has been detected. Repair : Replace the air filter restriction switch. Verify that the repairs eliminated the issue. Return the machine to service. Results : There is an active 107-3 fault code. A short circuit in the wiring harness has been detected. Repair : Repair or replace the wiring harness. Verify that the repairs eliminated the issue.
3. Check the Air Filter Restriction Switch A. Turn the keyswitch to OFF. B. Disconnect the air filter restriction switch from the wiring harness connector. C. Install a jumper wire in the wiring harness connector between the signal and ground wires. D. Turn the keyswitch to ON. E. Monitor Cat ET for active fault codes.	Diagnostic codes	Results : There is not an active 107-3 fault code. A failed air filter restriction switch has been detected. Repair : Replace the air filter restriction switch. Verify that the repairs eliminated the issue. Return the machine to service. Results : There is an active 107-3 fault code. An open circuit in the wiring harness has been detected. Repair : Repair or replace the wiring harness. Verify that the repairs eliminated the issue.