279C, 279C2, 289C, 289C2 and 299C Compact Track Loaders, 287C, 277C, 277C2, 287C2 and 297C Multi Terrain Loaders and 246C, 256C, 262C, 262C2 and 272C Skid Steer Loaders Machine Electronic Control System Caterpillar

Illustration 1	g01270821
Schematic of the Left Drive (Forward) Pump Solenoid Circuit

This diagnostic code is recorded when the ECM reads the current of the solenoid as being below normal.

The possible causes are listed:

• The energize circuit of the solenoid is open.

• The return circuit of the solenoid is open.

• The solenoid has failed.

• The ECM has failed. This is unlikely.

Note: The following procedure can create numerous related diagnostic codes. When all harnesses are reconnected, the related diagnostic codes will be shown as being not active. Clear all related diagnostic codes after this procedure is completed.

System Response:

The action lamp will flash. If the machine is traveling forward, the machine will be brought to a stop. The park brake will engage. If the machine is traveling in reverse, the machine will be limited to half speed.

Test Step 1. CHECK THE SOLENOID.

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

2. Disconnect the machine harness from the solenoid.

3. At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire K944-YL) to contact 2 (wire H801-PU).

4. Observe the status of the diagnostic code.

Expected Result:

The diagnostic code is active. Then, the diagnostic code is NOT active as the jumper wire is installed and removed.

Results:

• YES - The circuit is correct. The solenoid has failed.

  Repair: Repeat this test "CHECK THE SOLENOID" in order to verify that the solenoid has failed. Replace the solenoid.

  STOP

• NO - The diagnostic code remains active. Proceed to test step 2.

Test Step 2. CHECK THE SOLENOID CIRCUIT FOR AN OPEN.

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

2. Disconnect the negative battery cable and turn the key start switch to the OFF position.

3. At the machine harness connector for the solenoid, the jumper wire remains installed.

4. At J1 machine harness connector, measure the resistance from contact J1-50 (wire H801-PU) to J1-48 (wire K944-YL).

Expected Result:

The resistance should be less than 5 ohms.

Results:

• YES - The resistance is less than 5 ohms. The machine harness is correct. Proceed to test step 3.

• NO - The resistance measurement is NOT correct. There is an open circuit in the machine harness.

  Repair: The open is in the wire for the solenoid signal or in wire (H801-PU) of the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the contacts and clean the contacts of the harness connectors.

2. Reconnect all harness connectors.

3. Reconnect the negative battery cable and turn the key start switch to the ON position.

4. Clear all inactive diagnostic codes.

5. Operate the machine.

6. Stop the machine and place the parking brake switch in the ON position.

7. Check if the diagnostic code for the solenoid is active.

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.

  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

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

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the problem is not found, contact the Technical Communicator for your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, see Troubleshooting, Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP