PIN 3G6509 - Caterpillar

System Operation Description:Use the following diagnostic procedure in order to diagnose problems with the air inlet restriction switch.
Illustration 1 g01383087
Typical air inlet restriction switch and connectorThe air inlet restriction switch is used in order to warn the operator when the air filter element is plugged. The switch is a normally open switch. When the air flow restriction increases beyond 7.5 kPa (30 inch of H2O), the switch closes. The switch is latched in the closed position until the switch is reset.
Illustration 2 g01383334
Schematic for the air inlet restriction switchThe following components can cause an electrical problem with this circuit:
Electrical connector or wiring
Switch
Electronic Control Module (ECM)The most likely cause of a problem with the circuit is an electrical connector or wiring. The least likely cause of a problem is the ECM.Test Step 1. Check the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Illustration 3 g01214624
Location of the J1/P1 ECM connectors that are for the air inlet restriction switch (typical left side engine view)
Illustration 4 g01383382
Location of the air inlet restriction switch (typical engine view)
Thoroughly inspect the J1/P1 ECM connectors. Also, thoroughly inspect the connectors for the air inlet restriction switch. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 5 g01383393
Terminal locations at the P1 ECM connector that are for the switch circuits (P1-5) Digital return (P1-35) Air inlet restriction switch
Perform a 45 N (10 lb) pull test on each of the wires in the circuit for the suspect switch.
Check the allen head screw on each ECM connector for the proper torque. Also, check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The wiring and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the wiring and/or a connector.Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOPTest Step 2. Test the Switch for Proper Operation
Disconnect the P1 connector.
Connect the leads of a multimeter between terminals P1-5 (digital return) and P1-35 (air inlet restriction switch). Ensure that the switch is in the reset position.Note: Wiggle the harnesses during the following measurements in order to reveal any intermittent short condition.
Apply a vacuum of 7.5 kPa (30 inch of H2O) in order to activate the switch. The switch will latch in the closed position.Note: Do not exceed 8.7 kPa (35 inch of H2O). Damage to the switch may occur.
Measure the resistance between terminals P1-5 (digital return) and P1-35 (air inlet restriction switch).Expected Result:One resistance measurement indicates an open circuit. The other resistance measurement indicates