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

CID 0444 FMI 03 Magnetic Switch (Start Relay) Voltage Above Normal - Test

Usage:

24H 7KK

Show/hide table




Illustration 1	g00494026
Schematic For Start Relay

This fault is recorded when there is voltage in the circuit for the start relay, and the ECM does not expect the voltage. The start relay is located in the relay panel on the right rear side of the engine compartment. Connector J1-8 (wire 306-GN) of the ECM relates to this detected fault. This fault causes the engine to crank continuously.

CHECK FOR A SHORT.
1. Turn the key start switch to the OFF position.
1. Disconnect the connector of the start relay from the machine harness.
1. Turn the key start switch to the ON position.
1. At the machine harness connector for the start relay, measure the voltage from contact 1 (wire 306-GN) to frame ground.
  Expected Result: Voltage should not be present.
  Results:
  - OK - Voltage is NOT present. The fault is not currently present. Clean the contacts of the connector. Reconnect the start relay to the machine harness. Clear the CID 0444 FMI 03 service code. The initial fault was probably caused by a poor electrical connection. Resume normal machine operation.
  - NOT OK - Voltage is present. Proceed to Step 2.

CHECK THE SIGNAL VOLTAGE.
1. Turn the key start switch to the OFF position. The start relay remains disconnected from the machine harness.
1. Disconnect the ECM from the machine harness.
1. Turn the key start switch to the ON position.
1. At the machine harness connector for the start relay, measure the voltage from contact 1 (wire 306-GN) to frame ground.
  Expected Result: Voltage is present.
  Results:
  - YES - Voltage is present. Wire 306-GN is shorted in the machine harness. Repair the machine harness or replace the machine harness.
  - NO - Voltage is NOT present. There is a fault. It is unlikely that the ECM is faulty. Perform this complete procedure again. If the cause of the fault is not found, replace the ECM. See Testing and Adjusting, "ECM Replacement".