C15 – Electronic Service Tool Will Not Communicate with ECM

Probable Causes

• Configuration for the communications adapter
• Electrical connectors
• Communication adapter and/or cables
• Electrical power supply to the service tool connector
• Cat ET and related hardware
• Electrical power supply to the ECM
• Override switches
• Personality module (flash file)
• ATA Data Link

Recommended Actions

Start the engine. If the engine starts, but the ECM will not communicate with the Caterpillar Electronic Technician (Cat ET), continue with this procedure.
If the engine will not start, refer to Troubleshooting, “Engine Cranks but Will Not Start”. If the engine will not crank, refer to Troubleshooting, “Engine Will Not Crank”.

Configuration for the Communications Adapter

1. Access “Preferences” under the “Utilities” menu on Cat ET.
2. Verify that the correct “Communications Interface Device” is selected.
3. Verify that the correct “Port” is selected for use by the communication adapter.
Note: The most commonly used port is “COM 1”.
4. Check for any hardware that is utilizing the same port as the communications adapter. If any
devices are configured to use the same port, exit or close the software programs for that device.

Electrical Connectors

Check for correct installation of the J1/P1 and J2/P2 ECM connectors and the service tool connector.
Refer to Troubleshooting, “Electrical Connectors – Inspect”.

Communication Adapter and/or Cables

1. If you are using a Communication Adapter II, ensure that the firmware and driver files for the
communication adapter are the most current files that are available. If the firmware and driver files do not match, the communication adapter will not communicate with Cat ET.

2. Disconnect the communication adapter and the cables from the service tool connector.
Reconnect the communication adapter to the service tool connector.

3. Verify that the correct cable is being used between the communication adapter and the
service tool connector. Refer to Troubleshooting,
“Electronic Service Tools”.

Electrical Power Supply to the Service Tool Connector

Verify that battery voltage is present between terminals A and B of the service tool connector. If
the communication adapter is not receiving power, the display on the communication adapter will be blank.

Cat ET and Related Hardware

In order to eliminate Cat ET and the related hardware as the problem, connect Cat ET to a
different engine. If the same problem occurs on a different engine, check Cat ET and the related
hardware in order to determine the cause of the problem.

Electrical Power Supply to the ECM
Check power to the ECM. Refer to Troubleshooting, “Ignition Key Switch Circuit and Battery Supply Circuit – Test”.

Note: If the ECM is not receiving battery voltage, the ECM will not communicate.

Override Switches

1. Ensure that the ignition key switch is in the ON position. Ensure that there are no override switches that are creating the problem.

2. Ensure that there are no aftermarket devices that are preventing battery voltage from reaching the ECM.

3. Start the engine and then connect Cat ET. Some type of override switch is interrupting the power
to the ECM under the following condition: If communication occurs with the engine running
but no communication occurs with the key switch in the ON position.

Personality Module (Flash File)

Ensure that the correct personality module is properly installed in the ECM.

Note: The personality module that is provided in a new ECM is blank. The engine will not start and
the engine will not communicate with Cat ET until the personality module has been flashed. Refer to
Troubleshooting, “Flash Programming”.

ATA Data Link

Troubleshoot the ATA Data Link for possible problems. Refer to Troubleshooting, “ATA (SAE
J1587 / J1708) Data Link Circuit – Test”.

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