Asphalt Pavers Conveyor Electronic Control System Caterpillar

Illustration 1	g01117474

Sensor Supply Voltage

This diagnostic code is recorded when the ECM reads the voltage of the sensor supply circuit as above normal. The sensor supply is a power supply that is internal to the ECM. The sensor supply provides +8 DCV to operate the PWM buffers. The ECM monitors this output voltage and records a diagnostic code when the voltage is higher than +8.5 DCV

The possible causes of this diagnostic code are:

• The sensor supply circuit is shorted to +V.

• The ECM has failed. This is unlikely.

System Response:

The results of this diagnostic code are:

• The conveyor diagnostic lamp is ON.

• Improper operation of the sensors, which could cause the conveyors and augers to perform in an unpredictable manner.

Note: Ensure that the diagnostic code CID 061 FMI F03 for the sensor supply is on hold and that the diagnostic code present indicator on the ECM display is ON. Test Step 1 can cause other diagnostic codes to become active. Ignore these created diagnostic codes. When the procedure is completed, clear the created diagnostic codes.

Test Step 1. Check Sensor Supply Circuit For Short To +V

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

2. Disconnect the machine harness from the ECM.

3. At the machine harness connector, measure the resistance from the sensor supply circuit at harness connector contact 40 (wire P128-BU) to all other possible sources of +V. The possible sources of positive voltage are harness connector contacts 1, 10, 11, 32, 33, 34, 36, 37 and 38.

Expected Result:

Each resistance should be greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step 2.

• NOT OK - One or more resistance measurements is less than 5000 ohms.

  Repair: There is a short in the machine harness. The short is between the sensor supply circuit at harness connector contact 40 (wire P128-BU) and the circuit with the low resistance measurement. Repair or replace the machine harness.

  Stop.

Test Step 2. Check To See If Diagnostic Code Remains

1. Clean the contacts of the harness connectors.

2. Reconnect all harness connectors.

3. Turn the key start switch to the ON position.

4. Enter service mode 1 on the ECM three digit display. Clear all inactive diagnostic codes.

5. Operate the machine.

6. Check to see if the CID 061 FMI F03 diagnostic code for the sensor supply is present (diagnostic code present indicator ON).

Expected Result:

The CID 061 FMI F03 diagnostic code for the sensor supply is not present.

Results:

• OK - The CID 061 FMI F03 diagnostic code for the sensor supply is not present. The machine harness and the ECM are operating properly.

  Repair: 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 reconnected. Resume normal machine operation.

  Stop.

• NOT OK - The CID 061 FMI F03 diagnostic code for the sensor supply is still present.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Refer to the Electrical System Schematic for this machine and check all involved wiring harness connectors and wiring. Ensure that the connector contacts are clean and in good condition. Ensure that all machine harness wiring is intact and in good condition. If the cause of this error code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace" in this manual.

  Stop.