TH220B, TH330B, TH340B, TH350B, TH355B, TH360B, TH460B, TH560B and TH580B Telehandlers Caterpillar

Illustration 1	g00917007
Schematic of the Pressure Switch (Left Stabilizer)

A diagnostic code is recorded when a loss of signal is recorded by the pressure switch (left stabilizer).

Test Step 1. CHECK THE SWITCH

1. At the switch, measure the resistance from frame ground to the input of the pressure switch while the stabilizer is NOT activated.

2. At the switch, measure the resistance from frame ground to the input of the pressure switch while the stabilizer is activated.

Expected Result:

The measured resistance at the switch should be greater than 5,000 ohms while the stabilizer is NOT activated. The measured resistance at each switch should be less than 5 ohms while the stabilizer is activated.

Results:

• OK - The measured resistance at each switch is greater than 5,000 ohms while the stabilizer is NOT activated. The measured resistance at each switch is less than 5 ohms while the stabilizer is activated. The switch is correct. The machine harness is not correct.

  Repair: Repair the machine harness or replace the machine harness.

  Stop.

• NOT OK - The measured resistance at the switch is NOT greater than 5,000 ohms while the stabilizer is NOT activated. The measured resistance at the switch is NOT less than 5 ohms while the stabilizer is activated. The switch is NOT correct.

  Repair: Replace the switch.

  Stop.

Test Step 2. VERIFY THAT THE DIAGNOSTIC CODE IS PRESENT.

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

2. Inspect the connectors and inspect the contacts.

3. Connect the machine harness to the control module.

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

5. Enter the service mode.

6. Operate the machine.

7. Check for active diagnostic codes. Note the active diagnostic codes.

Expected Result:

The diagnostic code is active.

Results:

• YES - The diagnostic code is active. The condition has not been corrected. The ECM may have failed. Proceed to test step 3.

• NO - The diagnostic code is not active. The diagnostic code was caused by a poor electrical connection.

  Repair: Clear the diagnostic code.

  Stop.

Test Step 3. VERIFY THAT THE ECM HAS FAILED.

1. Connect the machine harness to the control module.

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

3. Verify that the diagnostic code is present. Verify that the diagnostic code is active.

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

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

6. Verify that the diagnostic code is present. Verify that the diagnostic code is active.

Expected Result:

The diagnostic code is active.

Results:

• YES - The diagnostic code is active. The ECM has failed.

  Repair: Replace the ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  Stop.

• NO - The diagnostic code is not active. Clear the diagnostic code. Stop.