416E, 420E and 430E Backhoe Loaders MID 039 - CID 0702 - FMI 02 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g01308456
Schematic of the Transmission Gear Sensor

This diagnostic code is associated with the "Transmission Gear Selector Sensor" switch on the "standard shift" transmission only. This Diagnostic code is recorded when the ECM reads the Signal from the sensor and the ECM determines that the signal is erratic, intermittent, or incorrect.

The possible causes of this diagnostic code are listed below:

• There is a wire that is shorted to the ground circuit while the machine is in operation.

• There is a wire that is shorted to the +battery circuit.

• The Diode Block for the transmission is faulty or the Diode Block for the transmission has failed.

• The "FNR" Switch in the Shift Handle is faulty or the "FNR" Switch in the Shift Handle has failed.

• An open circuit exists.

• 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 0702 FMI 02 is active before performing this procedure.

Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.

System Response:

The diagnostic code of CID 0702 FMI 02 will be logged in the internal memory of the ECM.

Test Step 1. CHECK THE VOLTAGE AT THE SWITCH

1. Turn the key start switch to the ON position. Do not turn over the engine.

2. While the machine is in the forward position, measure voltage at pin 5 of the "FNR" switch.

3. While the machine is in the reverse position, measure voltage at pin 6 of the "FNR" switch.

4. While the machine is in the neutral position, measure voltage at pin 5 and pin 6 of the "FNR" switch.

Expected Result:

Pins 5 and 6 have a voltage of approximately 12 volts (battery voltage) in the "foward" and "reverse" positions. There is no voltage in the "neutral" position.

Results:

• OK - All of the voltage measurements are correct. Proceed to Test Step 2.

• NOT OK - One of the measurements does not agree with the expected result.

  Repair: The "Transmission Diode Block " switch ("FNR") must be replaced.

  STOP

Test Step 2. CHECK THE HARNESS FROM THE KEY START SWITCH TO THE BATTERY

Illustration 2	g02121733

1. The key start switch remains in the ON position.

2. Measure the voltage at pin 2 of the diode block when the machine is in the reverse and neutral positions.

3. Measure the voltage at pin 3 of the diode block when the machine is in the forward and the neutral position.

4. Measure the voltage at pin 4 of the diode block when the "FNR" switch of the machine is moved to all positions.

5. Measure the voltage at pin J2-1 of the Machine ECM in all position.

Expected Result:

The voltage lines up with the "Forward" and "Reverse" positions on the table above. Voltage should not be present when the machine is in the "Neutral" position.

Results:

• OK - The voltage agrees with the information from the table above. Proceed to Test Step 5.

• NOT OK - Voltage is present when the machine is in the Neutral position. There is a short in the harness from the "FNR" switch.

  Repair: Repair the harness or replace the harness. Repair the "Transmission Diode Block " switch ("FNR") or replace the "Transmission Diode Block " switch ("FNR").

  STOP

• NOT OK - There is voltage at pin 4 but no voltage at pin J2-1. There is a open in the harness from the diode block to the Machine ECM.

  Repair: Repair the harness or the diode. Replace the harness or the diode.

  STOP

• NOT OK - There is voltage at pin J2-1 in the neutral position. There is a short in the harness from the diode to the Machine ECM.

  Repair: Repair the harness or the diode or replace the harness or the diode.

  STOP

Test Step 3. CHECK THE GROUND CIRCUITS.

1. Turn the key start switch to the OFF position.

2. Measure continuity to ground at pin J2-26 in the forward position and pin J2-27 in the reverse position.

3. Measure continuity to ground at pin J2-26 and pin J2-27 in the neutral position.

   Note: There should be no continuity in the neutral position.

Expected Result:

The resistance is less than 5 ohms.

Results:

• OK - The resistance is less than 5 ohms. Proceed to Test Step 5.

• NOT OK - The resistance is less than 5 ohms. There is continuity to the ground contact with the shift control in the neutral position. Proceed to Test Step 4.

Test Step 4. CHECK THE HARNESS

1. Turn the key start switch to the OFF position.

2. Disconnect wire H731-GY and wire G750-BU from the Machine ECM and the "FNR" switch.

3. Measure continuity to ground contact on each wire. Unplug the "FNR" switch.

4. Measure continuity from one end of the wire to the other end of the wire.

5. Measure continuity to ground at the "FNR" switch in each position. Refer to 1 for valid readings at the pins.

Expected Result:

The "FNR" switch is providing a ground in the forward position and reverse position.

Results:

• OK - There is no continuity to ground when the "FNR" switch is unplugged. The measurements across the wires are less than 5 ohms. Proceed to Test Step 5.

• NOT OK - There is continuity to ground when the "FNR" switch is unplugged.

  Repair: Repair the harness or replace the harness.

  STOP

• NOT OK - The measurement across one of the wires is greater than 5 ohms. The measurement across both of the wires is greater than 5 ohms. There is a open in the wire.

  Repair: Repair the harness or replace the harness.

  STOP

• NOT OK - There are one or more positions that do not line up with the continuity checks at the "FNR" switch.

  Repair: Replace the "FNR" switch.

  STOP

Test Step 5. CHECK IF THE DIAGNOSTIC CODE REMAINS

1. Clean the contacts of the harness connectors.

2. Reconnect all harness connectors.

3. Observe the status of the diagnostic code.

4. Operate the machine.

5. Observe the status of the diagnostic code.

Expected Result:

The diagnostic code is no longer active.

Results:

• YES - The diagnostic code is NO longer active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected And then reconnected. Resume normal machine operation.STOP

• NO - The diagnostic code has not been corrected. The Machine ECM has failed.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Prior to replacing an ECM, always contact your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP