RENR5042-02 183 Troubleshooting Section Test Step 1. Inspect the Throttle’s Components D. Move the throttle to low idle. Adjust the throttle linkage and adjust the low idle set screw until the “Throttle Position” is zero percent. A. Turn the keyswitch to the OFF position. E. Increase the throttle. Verify that the value of the “Throttle Position” increases. B. Inspect the throttle linkage and related components for the following conditions: Loose Expected Result: Bent When the throttle is at low idle, the “Throttle Position” is zero percent. As you increase the throttle, the value of the “Throttle Position” increases. Broken Results:
Missing OK – When the throttle is at low idle, the “Throttle Position” is zero percent. As you increase the throttle, the value of the “Throttle Position” increases. The low idle adjustment is correct. Proceed to Test Step 4. Worn Expected Result: The throttle linkage and related components are in good condition. Not OK When the throttle is at low idle, the “Throttle Position” is zero percent. Alternatively, as you increase the throttle, the value of the “Throttle Position” does not increase. There is a problem with the throttle position sensor. Results: OK – The throttle linkage and related components are in good condition. Proceed to Test Step 2.
Not OK The throttle linkage and related components are not in good condition. Repair: Refer to Troubleshooting, “Throttle Postion Sensor Circuit - Test”. STOP. Repair: Repair the throttle linkage. Replace parts, if necessary. Continue with this procedure when the components for the throttle linkage are in good condition. Test Step 4. Adjust the Throttle at High Idle A. Move the throttle to high idle. Adjust the throttle linkage and/or adjust the high idle set screw until the “Throttle Position” is 100 percent. STOP. Test Step 2. Determine the Type of Calibration Note: When you adjust the high idle on some types of linkage, the low idle adjustment may change.
Determine the type of calibration to be performed. B. Verify that low idle is correctly adjusted. Make adjustments, if necessary. Results: Mechanical Proceed to Test Step 3. Expected Result: Electronic Proceed to Test Step 5. When the throttle is at high idle, the “Throttle Position” is 100 percent. When the throttle is at low idle, the “Throttle Position” is zero percent. Test Step 3. Adjust the Throttle at Low Idle Results: A. Connect Cat ET to the service tool connector. Refer to Troubleshooting, “Electronic Service Tools”. OK – When the throttle is at high idle, the “Throttle Position” is 100 percent. When the throttle is at low idle, the “Throttle Position” is 0 percent.
Calibration of the throttle is complete. STOP. B. Turn the keyswitch to the ON position. Do not start the engine. C. Observe the value of the “Throttle Position” on Cat ET. Not OK – The high idle position and/or the low idle position cannot be adjusted to the specification. An electronic calibration is required. Proceed to Test Step 5.