C1.7 and C2.2 Industrial Engine Caterpillar

Idle Validation - Test

Usage:

C1.7 G34

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Trouble Codes for the Idle Validation Switches
J1939 Code	Code Description	Comments
558-3	Accelerator Pedal 1 Low Idle Switch : Voltage Above Normal	The Electronic Control Module (ECM) detects the following condition: The Idle Validation Switch 1 (IVS) is open for at least 0.5 seconds when the engine is at low idle. An active diagnostic code will be generated.
558-4	Accelerator Pedal 1 Low Idle Switch : Voltage Below Normal	The Electronic Control Module (ECM) detects the following condition: The Idle Validation Switch 1 (IVS) is closed for at least 0.5 seconds when the engine is above the configured IVS threshold. An active diagnostic code will be generated.
2970-3	Accelerator Pedal 2 Low Idle Switch : Voltage Above Normal	The Electronic Control Module (ECM) detects the following condition: The Idle Validation Switch 2 (IVS) is open for at least 0.5 seconds when the engine is at low idle. An active diagnostic code will be generated.
2970-4	Accelerator Pedal 2 Low Idle Switch : Voltage Below Normal	The Electronic Control Module (ECM) detects the following condition: The Idle Validation Switch 2 (IVS) is closed for at least 0.5 seconds when the engine is above the configured IVS threshold. An active diagnostic code will be generated.
Follow the troubleshooting procedure to identify the root cause of the fault.

The IVS may be installed. The IVS is required for mobile applications. The IVS is part of the throttle position sensor. The IVS is CLOSED when the low idle is set.

The configuration parameters for the throttle and for the IVS thresholds are programmed into the ECM. Use the electronic service tool to display the configuration parameters for the throttle and for the IVS.

If the IVS operates outside of the programmed range, then the engine speed may not respond to changes in the throttle position.

The electronic service tool may be used for the following:

If necessary, reset the IVS threshold for an existing IVS.
If necessary, view the IVS change point and reset the IVS thresholds when a new throttle assembly is installed.

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Illustration 1	g06014416
Schematic of the IVS circuits

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Illustration 2	g06036184
P1 pinouts for the IVS circuits (37) Idle validation 2 (40) Idle validation 1

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Table 2
IVS Diagnostic Code Conditions
Engine Speed	Switch Condition	Diagnostic Code
Low idle	Closed	None (normal condition)
Low idle	Open	558-3 (IVS 1) 2970-3 (IVS 2)
Greater than low idle	Closed	558-4 (IVS 1) 2970-4 (IVS 2)
Greater than low idle	Open	None (normal condition)

Complete the procedure in the order in which the steps are listed.

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Table 3
Troubleshooting Test Steps	Values	Results
1. Check the Parameters for the Idle Validation Switches A. Use the electronic service tool to check the parameters for the IVS and low idle settings. Refer to Troubleshooting, "Customer Specified Parameters".	IVS parameters	Result: The parameters are set correctly. Proceed to Test Step 2 Result: The parameters are not set correctly. Repair: Use the electronic service tool to set the parameters for the IVS and low idle. Start the engine and operate the throttle over the full operating range. Use the electronic service tool to verify that the fault has been eliminated.
2. Inspect Electrical Connectors and the Harness A. Inspect the P1/J1 connectors, the harness and all the connectors for the IVS. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. B. Perform a 45 N (10 lb) pull test on each wire in the ECM connector that is associated with the suspect idle validation switch. C. Check the screw for the ECM connector for the correct torque of 6 N·m (53 lb in). D. Check the harness for abrasion and pinch points from the throttle switch to the ECM.	Loose connection or damaged wire	Result: Faults found in harness or connectors. Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all the seals are correctly in place and ensure that the connectors are correctly connected. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault. Result: No harness or connector faults found. Proceed to Test Step 3.
3. Check for Active Diagnostic Codes and/or Recently Logged Diagnostic Codes A. Connect the electronic service tool to the diagnostic connector. B. Turn the keyswitch to the ON position. C. Monitor the active diagnostic code screen on the electronic service tool. Check and record any active diagnostic codes. Note: Wait at least 30 seconds in order for the diagnostic codes to become active. Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are a poor connection in a connector.	Diagnostic codes	Result: A 558-3 or a 2970-3 diagnostic code is active or recently logged Proceed to Test Step 4. Result: A 558-4 or a 2970-4 diagnostic code is active or recently logged Proceed to Test Step 6. Result: No diagnostic codes are active or recently logged. The fault may be intermittent. Repair: Inspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".
4. Create a Short at the Switch Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the suspect IVS. C. Fabricate a jumper wire that is 150 mm (6 inch) long. D. Install the jumper wire between the two terminals on the harness connector for the suspect switch. E. Connect the electronic service tool to the diagnostic connector. F. Turn the keyswitch to the ON position. Do not start the engine. G. Select the "Throttle status" function on the electronic service tool. Select "Status" function and then select "Throttles" function. H. Observe the status of the IVS with the jumper installed. I. Turn the keyswitch to the OFF position. Remove the jumper wire.	Short circuit	Result: The service tool indicates "In Low Idle" with the jumper installed. The fault is in the IVS. Repair: Replace the suspect IVS. Start the engine and operate the throttle over the full operating range. Use the electronic service tool to verify that the fault has been eliminated. Result: The service tool indicates "Not In Low Idle" with the jumper installed. 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 suspect IVS. C. Disconnect the P1 connector from the ECM. D. Use a suitable multimeter to take the following resistance measurements: • The suspect switch connector to the appropriate terminal on the P1 connector. • The suspect switch connector to machine ground. Refer to Illustration 1.	Less than 2.0 Ohms	Result:At least one of the resistance measurements is greater than 2.0 Ohms. There is an open circuit or high resistance in the wiring for the suspect IVS. Repair: Replace the faulty wiring. Start the engine and operate the throttle over the full operating range. Use the electronic service tool to verify that the fault has been eliminated. Result: Both resistance measurements are less than 2.0 Ohms. Contact the Dealer Solutions Network (DSN).
6. Create an Open Circuit at the Switch Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the suspect IVS. C. Connect the electronic service tool to the diagnostic connector. D. Turn the keyswitch to the ON position. Do not start the engine. E. Select the "Throttle status" function on the electronic service tool. Select "Status" function and then select "Throttles" function. F. Observe the status of the IVS with the connector disconnected. G. Turn the keyswitch to the OFF position. Remove the jumper wire.	Open circuit	Result: The electronic service tool indicates "Not in Low Idle" with the connector disconnected. The fault is in the IVS. Repair: Replace the suspect IVS. Start the engine and operate the throttle over the full operating range. Use the electronic service tool to verify that the fault has been eliminated. Result:The electronic service tool indicates "In Low Idle" with the connector disconnected. Proceed to Test Step 7.
7. Check the Wiring for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector for the suspect IVS. C. Disconnect the P1 connector. D. If the fault is on IVS 1, use a multimeter to check the resistance between P1:40 and all other terminals on the P1 connector. E.If the fault is on IVS 2, use a multimeter to check the resistance between P1:37 and all other terminals on the P1 connector.	Short circuit.	Result: At least one of the resistance measurements is less than 100 Ohms. There is a short in the wiring for the suspect IVS. Repair: Replace the faulty wiring. Start the engine and operate the throttle over the full operating range. Use the electronic service tool to verify that the fault has been eliminated. Result: The measured resistance in all wires is greater than 100 Ohms. The fault is in the ECM. Contact the Dealer Solutions Network (DSN).