3500B Series II Marine Engines Caterpillar

The Electronic Control Module (ECM) contains no moving parts. Replacement of the ECM can be costly. Replacement can also be a time consuming task. Follow the troubleshooting procedures in this manual in order to be sure that replacing the ECM will correct the problem. Verify that the suspect ECM is the cause of the problem.

Note: Ensure that the ECM is receiving power and that the ECM is properly wired to the negative battery circuit before a replacement of the ECM is attempted. Refer to Troubleshooting, "Electrical Power Supply".

A spare ECM can be used to determine if the ECM is faulty. Install a spare ECM in place of the suspect ECM. Flash program the correct flash file into the spare ECM. Program the parameters for normal operation of the engine. The parameters must match the parameters in the suspect ECM. Refer to the following test steps for details. If the spare ECM resolves the problem, connect the suspect ECM. Verify that the problem returns. If the problem returns, replace the suspect ECM.

Note: When a new ECM is not available, you may need to remove an ECM from an engine that is not in service. The interlock code for the replacement ECM must match the interlock code for the suspect ECM. Be sure to record the parameters from the replacement ECM on the "Parameters Worksheet". Use the "Copy Configuration/ECM Replacement" feature that is found under the "Service" menu on the Caterpillar Electronic Technician (ET).

Perform the following procedure in order to replace the ECM.

1. Record the configuration data:

   1. Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".

   2. Print the parameters from the "Configuration" screen on Cat ET. If a printer is unavailable, record all of the parameters. Record any logged diagnostic codes and logged event codes for your records. Record the injector codes from the "Calibrations" screen in the "Service" menu on Cat ET.

      Note: The injector trim code is a number that is found on each of the unit injectors. The ECM uses this number to compensate for manufacturing variations between individual injectors. If you replace any of the unit injectors, you must reprogram the trim code for the new injectors. Also, if you replace the ECM, you must reprogram all of the trim codes.

   3. Use the "Copy Configuration/ECM Replacement" feature that is found under the "Service" menu on Cat ET. Select "Load from ECM" in order to copy the configuration data from the suspect ECM.

      Note: If the "Copy Configuration" process fails and the parameters were not obtained in Step 1.b, the parameters must be obtained elsewhere. Some of the parameters are stamped on the engine information plate. Most of the parameters must be obtained from the factory.

2. Remove the ECM.

   1. Remove electrical power from the ECM.

   2. Disconnect the ECM connectors J1/P1 and J2/P2.
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      NOTICE
      Use a suitable container to catch any fuel that might spill. Clean up any spilled fuel immediately.

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      NOTICE
      Do not allow dirt to enter the fuel system. Thoroughly clean the area around a fuel system component that will be disconnected. Fit a suitable cover over disconnected fuel system component.

   3. Remove the fuel lines from the ECM (if equipped).

   4. Remove the mounting bolts from the ECM.

   5. Disconnect the ECM ground strap from the engine.

3. Install the replacement ECM.

   1. Use the old mounting hardware to install the replacement ECM. The mounting hardware should be free of damage.

   2. Reconnect the fuel lines (if equipped).

   3. Ensure that the ECM mounting hardware is installed correctly. The fuel lines should not be putting tension on the ECM. The rubber grommets are used to protect the ECM from excessive vibration. The ECM should be able to drift in the rubber grommets. If the ECM cannot be moved slightly in the grommets, check that the fuel lines are not pulling the ECM against one side of the grommets.

   4. Install the ECM ground strap on the engine.

   5. Connect the P1 and P2 connectors. Tighten the allen head screws for each ECM connector to the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

4. Restore electrical power to the ECM.

5. Configure the replacement ECM:

   1. Flash program the flash file into the ECM. Refer to Troubleshooting, "Flash Programming" for the correct procedure.

   2. Use Cat ET to match the engine application and the interlock code if the replacement ECM was used for a different application.

   3. If the "Copy Configuration" process from Step 1.b was successful, return to the "Copy Configuration/ECM Replacement" screen on Cat ET and select "Program ECM". Proceed to Step 5.e when programming is complete.

   4. If the "Copy Configuration" process from Step 1.b was unsuccessful, manually program the ECM parameters. The parameters must match the parameters from Step 1.b.

   5. Program the engine monitoring system, if necessary.

   6. Calibrate the engine speed/timing. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".