C4.4 and C6.6 Engines Caterpillar

Mode Selection - Test

Usage:

C4.4 448

This procedure covers the following diagnostic code:

This procedure is only applicable to applications equipped with a mode selection switch.

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Table 1
Diagnostic Trouble Code for the Mode Selection Switch
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
2882-2	1743-2	Engine Alternate Rating Select : Erratic, Intermittent, or Incorrect	The Electronic Control Module (ECM) detects a combination of switch positions for the mode switches that has not been defined. If equipped, the warning lamp will come on and the ECM will log the diagnostic code. The ECM will return the engine to the last good mode selection or setting. The engine will start and the engine will default to the previous mode selection. The engine may operate at reduced speed or reduced power depending on the mode that is selected.
Follow the troubleshooting procedure to identify the root cause of the fault.

Use this procedure to check if the mode selection switch operates correctly.

The mode selection switch inputs provide the operator with the ability to select a maximum of four different modes of operation. Different modes of operation can be used giving the operator a means to select the most efficient method of completing the required work.

Each mode has a single fuel limit map, a rated speed, and a matched fuel delivery. Each mode also has a specific droop value for throttle 1 and throttle 2.

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Table 2
Mode Number	Switch 2	Switch 1	Enabled
Mode Number	Switch 2	Switch 1	Enabled
1	Open	Open	Y/N
2	Open	Closed	Y/N
3	Closed	Open	Y/N
4	Closed	Closed	Y/N

If a fault occurs in the circuit for either of the switches, the mode of operation will be different to the mode that was selected. If the mode of operation is not enabled on the application, a 2882-2 diagnostic code will become active.

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Illustration 1	g06103041
Schematic for the mode selection switch Not all connectors are shown. Refer to the appropriate Electrical Schematic

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Table 3
Troubleshooting Test Steps	Values	Results
1. Inspect Electrical Connectors and Wiring A. Turn the keyswitch OFF. B. Thoroughly inspect the P1 connector. Thoroughly inspect the mode switch connectors, plugs, and interconnections on the harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. C. Perform a 45 N (10 lb) pull test on each of the mode selector switch wires in the P1 connector. D. Check the screw for the ECM connector for the correct torque of 6 N·m (53 lb in). E. Check the harness for abrasions and for pinch points from the mode section switches to the ECM.	Loose connection or damaged wire	Result: There is a fault in a connector or the wiring. Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. Proceed to Test Step 2.
2. Check the Status of the Mode Selection Switch A. Turn the keyswitch to the OFF position. B. Connect the electronic service tool to the diagnostic connector. C. Turn the keyswitch to the ON position. D. Monitor the status screen on the electronic service tool. Cycle the mode switch to the ON position and to the OFF position.	Switch status changes	Result: The switch status changes on the electronic service tool as the mode switches are cycled. Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service. Result: The switch status does not change as the mode switches are cycled. Proceed to Test Step 3.
3. Insert a Jumper at the Suspect Mode Switch A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the suspect mode selection switch. C. Fabricate a jumper wire and install the jumper wire across the two contacts of the suspect switch. D. Turn the keyswitch to the ON position. Monitor the status screen on the electronic service tool. Connect the jumper wire and then disconnect the jumper wire. E. Turn the keyswitch to the OFF position. Remove the jumper wire.	Switch status "CLOSED" with jumper installed	Result: When the jumper wire is connected, the switch is in the CLOSED position. Repair: Replace the suspect mode selection switch. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: When the jumper wire is connected, the switch is in the OPEN position Proceed to Test Step 4.
4. Measure the Voltage at the Switch A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the mode selection switches. C. Turn the keyswitch to the ON position. D. Use the electronic service tool to turn both of the mode switches to the ON position. E. Measure the voltage from the input of each mode switch to a suitable ground.	At least 11 VDC for a 12 V system At least 22 VDC for a 24 V system	Result: One of the measured voltages is not within the expected range - The fault is in the wiring between the suspect mode switch and the ECM. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured voltages are within the expected range. Proceed to Test Step 5.
5. Check the Wiring for an Open Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the mode switches. C. Use a multimeter to measure the resistance between P1:62 and the ground terminal on mode switch 1. D. Use a multimeter to measure the resistance between P1:64 and the ground terminal on mode switch 2.	Less than 2 Ohms	Result: One of the measured resistances is greater than 2 Ohms - The fault is in the wiring between the suspect mode switch and the P1 connector. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All measured resistances are less than 2 Ohms. Proceed to Test Step 6.
6. Check the Wiring for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the mode switches. C. Disconnect the P1 connector from the ECM. D. Use a multimeter to measure the resistance between P1:62 and all other terminals on the P1 connector. E. Use a multimeter to measure the resistance between P1:64 and all other terminals on the P1 connector.	Greater than 1 k Ohm	Result: One of the measured resistances is less than 1 k Ohm. The fault is in the wiring between the ECM and the mode switch. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All measured resistances are greater than 100 Ohms. There is a fault in the ECM. Contact the Dealer Solutions Network (DSN).