AD55B Underground Articulated Truck Power Train Electronic Control System Caterpillar


Backup Alarm Always On

Usage:

AD55B JNW


System Operation Description:


Illustration 1g01340899

Schematic of the backup alarm

When the shift lever is in the REVERSE position, a signal is sent to the Power Train/Chassis Electronic Control Module (ECM). Circuit Breaker 6 supplies power to the backup alarm relay. Circuit Breaker 13 supplies power to the backup alarm relay coil. The Power Train/Chassis ECM switches the relay to frame ground. When the backup alarm relay is energized, +battery is applied to backup alarm.

If the backup alarm is always on, check these items:

  • The harness is shorted to +battery.

  • The harness is shorted to ground.

  • The backup alarm relay has failed.

  • The Power Train/Chassis ECM has failed.

Test Step 1. CHECK THE RELAY

  1. Turn the key start switch and the battery disconnect switch to the OFF position.

  1. Remove the backup alarm relay.

  1. Turn the battery disconnect switch and the key start switch to the ON position.

Expected Result:

The backup alarm is off.

Results:

  • YES - The backup alarm is off. Proceed to Test Step 2.

  • NO - The backup alarm is on. Proceed to Test Step 4.

Test Step 2. CHECK THE RELAY CONTACTS

  1. Turn the key start switch and the battery disconnect switch to the OFF position.

  1. The backup alarm relay remains removed.

  1. Check the resistance between contact 1 and contact 4 of the backup alarm relay.

Expected Result:

The resistance should be greater than 5 ohms.

Results:

  • YES - The resistance is greater than 5 ohms. Proceed to Test Step 3.

  • NO - The resistance is less than 5 ohms. The backup alarm relay has failed.

    Repair: Replace the backup alarm relay.

    STOP

Test Step 3. CHECK THE RETURN CIRCUIT OF THE BACKUP ALARM RELAY FOR A SHORT TO GROUND

  1. At the connector of the backup alarm relay measure the resistance between contact 2 (wire 331-OR) J2-12 and frame ground.

Expected Result:

The resistance should be greater than 5 ohms.

Results:

  • YES - The resistance is greater than 5 ohms. Proceed to Test Step 4.

  • NO - The resistance is less than 5 ohms. The machine harness has failed.

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

    STOP

Test Step 4. CHECK THE SIGNAL CIRCUIT OF THE BACKUP ALARM FOR A SHORT TO +BATTERY

  1. Turn the key start switch and the battery disconnect switch to the OFF position.

  1. Disconnect the machine harness from the backup alarm.

  1. At the connector of the backup alarm relay measure the resistance between contacts 1 (wire 120-YL) and contacts 4 (wire 612-GY), and between contacts 4 (wire 612-GY and contacts 5 (wire 126-PK) of the connector.

Expected Result:

Each resistance should be greater than 5 ohms.

Results:

  • YES - The resistance is greater than 5 ohms. Proceed to Test Step 5

  • NO - The resistance is less than 5 ohms. The machine harness has failed.

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

    STOP

Test Step 5. CHECK IF THE PROBLEM REMAINS

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

  1. Reconnect all the harness connectors.

  1. Operate the machine.

  1. Check to see if the fault still occurs.

Expected Result:

The fault is present.

Results:

  • YES - The fault is present. The fault has not been corrected. The Power Train/Chassis ECM may have failed.

    Repair: It is unlikely that the Power Train/Chassis ECM has failed. Exit this procedure and perform this procedure again. If the cause of the fault is not found, replace the Power Train/Chassis ECM. Refer to Systems Operation, Troubleshooting, Testing and Adjusting,, "Electronic Control Module ECM - Replace".

    STOP

  • NO - The fault is no longer present. The fault does not exist at this time.

    Repair: The initial fault 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

Caterpillar Information System:

AD55B Underground Articulated Truck Power Train Electronic Control System System Schematic
AD55B Underground Articulated Truck Power Train Electronic Control System Electronic Control Module (ECM) - Replace
AD55B Underground Articulated Truck Power Train Electronic Control System Hoist System Enable - Check
AD55B Underground Articulated Truck Power Train Electronic Control System Position Sensor (Body) - Calibrate
2007/06/11 Improved Monitoring for Primary and Secondary Steering is Now Used {4300, 4300, 7431}
AD55B Underground Articulated Truck Power Train Electronic Control System Transmission Clutch - Calibrate
AD55B Underground Articulated Truck Power Train Electronic Control System Speed Sensor - Replace
IT38H Integrated Toolcarrier and <BR>938H Wheel Loader <BR>Engine Supplement Turbocharger - Install
Diesel Particulate Filter Monitoring System {108F, 7490} Diesel Particulate Filter Monitoring System {108F, 7490}
D3K, D4K and D5K Track-Type Tractors Electrohydraulic Power Train System Piston Pump (Hydrostatic)
D3K, D4K and D5K Track-Type Tractors Electrohydraulic Power Train System Piston Pump (Hydrostatic)
IT38H Integrated Toolcarrier and <BR>938H Wheel Loader <BR>Engine Supplement Turbocharger - Remove
IT38H Integrated Toolcarrier and <BR>938H Wheel Loader <BR>Engine Supplement Engine Compartment Shield - Remove and Install
2007/01/01 Improved End Bits and the Rework Procedure are Available for the Bulldozer Blade {6804}
953D Track-Type Loader Hydraulic System Lift Circuit
D6T Track-Type Tractor Hydraulic System Control Valve (Bulldozer Tilt) - Standard
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 0562 - FMI 09
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1693 - FMI 00
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1693 - FMI 01
Replacement of the 124-4672 Pressure Sensor for the Payload Control System {1439, 7494} Replacement of the 124-4672 Pressure Sensor for the Payload Control System {1439, 7494}
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1693 - FMI 03
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1693 - FMI 04
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1693 - FMI 13
816F Series 2 Landfill Compactor, 815F Series 2 Soil Compactor and 814F Series 2 Wheel Dozer MID 081 - CID 1711 - FMI 03
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.