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

Illustration 1	g00528752
Schematic For The Shift Lever

This fault is recorded when the ECM reads the voltage of the circuit for the shift lever and the ECM determines that the voltage is above normal. There is a short to +battery.

The shift lever will not shift out of neutral when this fault condition is active. The possible causes of this fault are listed below:

• A wire is shorted to +battery in the machine harness.

• The ECM is faulty.

1. CHECK FOR SHORTED HARNESS

   1. Turn the disconnect switch to the OFF position.

   2. Disconnect machine harness connectors J1 and J2 from the ECM.

   3. Disconnect the machine harness from the lockup clutch solenoid.

   4. At machine harness connectors J1 and J2 for the ECM, measure the resistance between connector J1-15 (wire G939-PK) and all other contacts of the connectors.

      Note: If a short exists, it is most likely that the short is to the +battery circuit (contact 15) or another output circuit.

      Expected Result: The resistance is less than 5000 Ohms.

      Results:

      • YES - Resistance is less than 5000 Ohms the machine harness is faulty. Wire G939-PK is shorted within the machine harness between the shift lever and the ECM. Repair the machine harness or replace the machine harness.

      • NO - Resistance is greater than 5000 Ohms. The harness circuit resistance is correct. It is unlikely that the ECM is faulty. Perform the previous Steps again. If the cause is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".