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| Illustration 1 | g01448445 |
Schematic for the LH Brake Pedal Position Sensor | |
This diagnostic code is associated with the Left Brake Pedal Position Sensor. The FMI 03 means that the ECM has determined that the voltage of the circuit for the sensor is above normal.
The output frequency of the position sensor is approximately 500 hertz. The value of the sensor's duty cycle is approximately 50% in the depressed position. The duty cycle of the signal increases as the brake pedal is pressed. The value of the sensor's duty cycle is approximately 85% in the pressed position. The duty cycle of the signal decreases as the brake pedal is moved from the PRESSED position to the DEPRESSED position. The value of the sensor's duty cycle is approximately 15% in the depressed position.
The possible causes of this diagnostic code are listed below:
- The signal circuit for the sensor is open.
- The signal circuit for the sensor is shorted to the +battery circuit.
- The sensor has failed.
- The power circuit or the ground circuit has failed.
- The ECM has failed. This is unlikely.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0737 FMI 03 is active before performing this procedure.
Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.
Test Step 1. CHECK THE VOLTAGE AT THE SENSOR.
- Turn the disconnect switch and the key start switch to the ON position.
- Disconnect the sensor from the harness.
- At the harness connector for the sensor, measure the voltage between contact 1 (wire 164-WH) and contact 2 (wire C216-BK).
Expected Result:
The voltage measurement should be approximately battery voltage.
Results:
- YES - The voltage is approximately battery voltage. Proceed to Test Step 4.
- NO - The voltage is not approximately battery voltage. There is an open in the harness. Proceed to Test Step 2.
Test Step 2. CHECK FOR AN OPEN IN THE SUPPLY CIRCUIT.
- The key start switch and the disconnect switch remain in the ON position.
- The sensor remains disconnected from the harness.
- At the harness connector for the sensor, measure the voltage from contact 1 (wire 164-WH) to ground.
Expected Result:
The voltage measurement should be approximately battery voltage.
Results:
- YES - The voltage measurement is approximately battery voltage. Proceed to Test Step 3.
- NO - The voltage measurement is not approximately battery voltage.
Repair: The supply circuit is not correct. Repair the harness or replace the harness.
STOP
Test Step 3. CHECK FOR AN OPEN IN THE RETURN CIRCUIT.
- Turn the key start switch and the disconnect switch to the OFF position.
- The sensor remains disconnected from the harness.
- Disconnect the harness connectors from the ECM.
- At the harness connector for the sensor, measure the resistance from contact 2 (wire C216-BK) to ground.
Expected Result:
The resistance measurement should be less than 5000 Ohms.
Results:
- YES - The resistance measurement is less than 5000 Ohms. The harness is correct.
Repair: The ECM may have failed. It is unlikely that the ECM has failed. Recheck the status of the diagnostic code. If the diagnostic code remains present, exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the power train ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The resistance that is measured is not correct.
Repair: There is an open in the harness. The open is in the return circuit with the high resistance measurement. Repair the harness or replace the harness.
STOP
Test Step 4. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT.
- The key start switch and the disconnect switch remain in the OFF position.
- The harness connectors remain disconnected from the ECM.
- At the harness connector for the sensor, install a jumper wire from contact 3 (wire G746-WH) to ground.
- At the harness connector J2, measure the resistance from contact J2-18 (wire G746-WH) to ground.
Expected Result:
The resistance should measure less than 5.0 Ohms.
Results:
- YES - The resistance measures less than 5.0 Ohms. Proceed to Test Step 5.
- NO - The resistance measurement is greater than 5.0 Ohms.
Repair: There is an open in the signal circuit. Repair the harness or replace the harness.
STOP
Test Step 5. CHECK THE SIGNAL CIRCUIT FOR A SHORT.
- The disconnect switch and the key start switch remain in the OFF position.
- The harness connectors remain disconnected from the ECM.
- Remove the jumper wire from contact 3 to ground.
- At the harness connector for the ECM, measure the resistance for the signal contact of the sensor J2-18 (wire G746-WH) to all other J1 and J2 contacts.
Expected Result:
Each resistance measurement should be greater than 5000 Ohms.
Results:
- YES - Each resistance measurement is greater than 5000 Ohms.
Repair: The sensor has failed. Replace the sensor. Perform the calibration procedure for the position sensor. See Testing and Adjusting, "Position Sensor (Left Brake Pedal) (Operator Monitor) - Calibrate". Verify that the sensor corrected the problem. If the problem persists, exit this procedure and perform this procedure again. If the problem has not been found, replace the power train ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The resistance measures less than 5000 Ohms.
Repair: There is a short in the harness. The short is between the signal circuit and the circuit with the low resistance measurement. Repair the harness or replace the harness.
STOP