LEVER-THROTTLE 4P3539 - Caterpillar

System Operation Description:Terminal BN on the customer connector provides the primary throttle signal to the engine's Electronic Control Module (ECM). Terminal BM on the customer connector provides the secondary throttle signal to the engine's ECM. Both of the throttle signals should be a 500 Hz constant frequency signal with a pulse width that varies with the throttle signal. This output signal is referred to as a Pulse Width Modulated signal (PWM). This signal is expressed as a percentage between 0 percent and 100 percent.The throttle signal's duty cycle should be between 5 percent to 10 percent at low idle and 90 percent to 95 percent at high idle. The percent duty cycle is translated in the ECM into a throttle position of 0 percent to 100 percent. Use this procedure to troubleshoot an active diagnostic code of 91-08 Throttle Position signal abnormal or to troubleshoot an active diagnostic code of 1249-08 Secondary Throttle Position signal abnormal. The ECM will not respond to the throttle signal if there is an active 253-02 Personality Module mismatch.
Illustration 1 g01012536
Typical example
Illustration 2 g00725481
Throttle Position Versus PWM Input
Test Step 1. Check for Connector Damage.
Turn the Engine Control Switch (ECS) to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect the wiring and the connectors that are associated with the circuit. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details on inspecting wiring and connectors.
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 1 N m (53 9 lb in).
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are OK. If you are troubleshooting either the primary speed control or the secondary speed control from the customer, proceed to Test Step 2. If you are troubleshooting the local speed control on the instrument panel, proceed to Test Step 5.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Throttle Position on the Caterpillar Electronic Technician (ET).
Connect Cat ET to the service tool connector.
Turn the ECS to the STOP position.
Observe the position of the throttle on Cat ET.
Adjust the customer's throttle to the lowest setting.
Start at the lowest position. Slowly adjust the customer's throttle to the highest setting. Monitor the position of the throttle on Cat ET. Expected Result:The throttle position on Cat ET is 0 percent at the lowest setting and 0 to 100 percent as the throttle is adjusted to the highest setting.Results:
OK