SHIM 2274343 - Caterpillar

System Operation Description:The customer supplied Throttle Position Sensor provides a throttle signal to the ECM. The sensor output is a 4 to 20 mA signal. The signal is converted to a constant frequency signal with a pulse width that varies with the throttle position. This converted output signal is referred to as either Duty Cycle or as a Pulse Width Modulated signal. The signal is expressed as a percentage between 1 and 100 percent.The sensor will produce a duty cycle of 5 to 10 percent at the low idle setting. The sensor will produce a duty cycle of 90 to 95 percent at the high idle setting. The percent duty cycle is translated by the ECM into a throttle position of 0 to 100 percent.
Illustration 1 g00850901
Test Step 1. Check for Connector Damage.
Turn the circuit breaker for the battery to the OFF position.
Turn the Start/Stop Switch to the STOP position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and pinch points.Expected Result:The wiring and connectors should be free of the following problems: damage, abrasion, corrosion and incorrect attachment.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Stop.Test Step 2. Inspect the Throttle Assembly.
The throttle assembly should be free of the following problems: loose parts, bent parts, broken parts, missing parts and worn parts.Expected Result:The throttle assembly should operate smoothly without excessive drag. The throttle should return to the low idle position without assistance in less than one second.Results:
OK - The throttle assembly functions properly. Proceed to test step 3.
Not OK - The throttle assembly is not operating correctly.Repair: Repair the throttle assembly or replace the throttle assembly. The throttle assembly should operate smoothly without excessive drag. The throttle assembly should return to the low idle position without assistance in less than one second. Stop.Test Step 3. Check the Throttle Position with the ET.
Connect the ET to the service tool connector.
Connect the main power.
Observe the Throttle Position reading on the Electronic Service Tool Status screen.
Move the throttle to low idle. Slowly move the throttle toward the highest engine speed setting. Monitor the status screen.Expected Result:The Throttle Position should read 0.0 percent when the throttle is in the low idle position. The Throttle Position should move to 100 percent