24H Motor Grader Transmission Electronic Control System And Hydraulic Calibrations Caterpillar

CID 0468 FMI 04 Position Sensor (Brake Pedal) Voltage Below Normal - Test

Usage:

24H 7KK

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Illustration 1	g00514061
Schematic Of The Brake Pedal Position Sensor

This fault is recorded when the ECM reads the signal from the brake pedal position sensor (wire G745-PK) and the ECM determines that the signal is shorted to ground (FMI 04). The brake pedal position sensor is a PWM sensor. The signal wire of the brake pedal position sensor wire (G745-PK) connects to contact J2-5 of the ECM. The brake lamp does not work when this fault is active.

Service Notes: Ensure that the CID 0468 FMI 04 fault is on hold and that the fault present indicator is ON.

Note: Step 1 can create a CID 0468 FMI 03 fault. Clear the CID 0468 FMI 03 fault after this procedure is completed.

CHECK THE SENSOR.
1. Ensure that the CID 0468 FMI 04 fault is on hold and that the fault present indicator is ON.
1. Observe the ON/OFF status of the fault present indicator. Disconnect the machine harness from the sensor.
  Expected Result:The fault present indicator is OFF.
  Results:
  - YES - The fault present indicator is OFF. The fault is no longer present. The sensor is defective. Replace the sensor.
  - NO - Fault present indicator is ON. The fault remains present. The sensor is not causing the fault. Go to Step 2.

CHECK THE HARNESS.
1. The sensor remains disconnected from the machine harness. Turn the disconnect switch to the OFF position.
1. Disconnect the machine harness from the ECM.
1. At the machine harness connector for the ECM, measure the resistance between signal contact C (wire G745-PK) and frame ground.
  Expected Result:The resistance is less than 5000 Ohms.
  Results:
  - YES - Resistance is less than 5000 Ohms. The machine harness is defective. There is a short between frame ground and the signal circuit in the machine harness. Repair the machine harness or replace the machine harness.
  - NO - Resistance is greater than 5000 Ohms. The harness circuit resistance is correct. The ECM is defective. Replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace" .