CONNECTOR 4S6399 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the throttle position sensor or if the diagnostic code in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
91-8 Throttle Position Sensor abnormal frequency, pulse width, or period The Electronic Control Module (ECM) detects an incorrect frequency on the throttle signal or an incorrect duty cycle on the throttle signal. The frequency is below 150 Hz or the frequency in above 1000 Hz. The duty cycle is less than 5 percent or the duty cycle is greater than 95 percent. The ECM flags the throttle position as invalid data and a default value of zero percent is used. The engine speed is limited to low idle. The primary throttle signal to the engine's ECM is from terminal BN on the customer connector or from terminal BN on the connector for the EMCP electronic control. The throttle signal 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).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 the throttle position of 0 percent to 100 percent.
Illustration 1 g01630073
Typical example
Illustration 2 g00725481
Throttle Position Versus PWM Input
Illustration 3 g01630153
C-C18/(TB-C1 customer or L-C1/L-C2 EMCP 3) connectors
(Terminal BN) Primary throttle signal
Illustration 4 g01622856
Connector locations
(1) A-C1/E-C2/E-C1 Right hand cross over harness
(2) A-C2/J-C2/J-C1 Right hand cross over harness
(3) A-C90/P-C1 Connectors for the power distribution panel
(4) A-C91/P-C2 Connectors for the power distribution panel
(5) A-C60 Connector for the prelube motor
(6) A-C92/F-C1/F-C2/G-C6 Connectors for a RH Control panel
(7) C-C22 Primary ECM connector P2
(8) C-C15 Primary ECM connector P1
(9) C-C28 Secondary ECM connector P2
(10) C-C29 Secondary ECM connector P1
(11) C-C47 Connector for the power relay panel
(12) C-C17/F-C1/F-C2/G-C6 Connectors for a LH Control panel
(13) C-C18/(TB-C1 customer or L-C1/L-C2 EMCP 3) connectors
(14) C-C2/J-C1/J-C2 Left hand cross over harness
(15) C-C1/E-C1/E-C2 Left hand cross over harness Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the Engine Control Switch (ECS) to the OFF position.
Thoroughly inspect the ECM connector J1/P1. Inspect the wiring and the connectors that are associated with the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM. 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. Proceed to Test Step 2.
Not OK - The connectors and/or wiring need repair.Repair: