Electronic Modular Control Panel II (EMCP II) For PEEC Engines Caterpillar

Illustration 1	g00597815
Schematic For Oil Step Relay (OSR)

The oil step relay (OSR) is used by the GSC for the activation of the close-for-rated speed contacts of the PEEC ECM. When the contacts are activated, the PEEC ECM increases the engine speed from idle speed to rated speed. The output of the oil step relay is rated at 1 ampere. The OSR is located within the relay module.

The GSC activates the OSR when the engine oil pressure is greater than the setpoint for low oil pressure shutdown at idle speed (P14). (Also, "K1" is showing on the lower display.) This closes the contacts of the OSR. Also, the PEEC electronic control module places the engine at rated speed.

The GSC does not activate the OSR when the engine oil pressure is less than the setpoint for low oil pressure shutdown at idle speed (P14). (Also, "K1" is not showing on the lower display.) This opens the contacts of the OSR. Also, the PEEC electronic control module places the engine at idle speed.

Note: Whenever the GSC activates the OSR, "K1" is shown on the lower display. "K1" is also shown on the lower display when the GSC attempts to activate the OSR. When the OSR is not activated, "K1" is not shown.

Procedure

The following condition is a possible cause of a CID "441" FMI "12".

• A coil is open on the OSR.

• A coil is shorted on the OSR.

The following response is the system response to this fault while the OSR is activated:

• If a CID 441 FMI 12 occurs, then the engine speed drops from rated speed to idle speed.

The following response is the system response to this fault while the OSR is not activated:

• If a CID 441 FMI 12 occurs, then the engine is able to start but the engine is unable to reach rated speed.

The GSC treats this diagnostic code as an alarm fault. Active alarm faults are shown on the display when the alarm codes key is pressed. Also, the active alarm faults are shown when the ECS is in any position except the OFF/RESET position. Clear the diagnostic code from the fault log after troubleshooting is complete.

1. Check the status of the diagnostic code (Active/Inactive).

   1. Turn the ECS to OFF/RESET and then turn the ECS to STOP.

   2. Press the alarm codes key.

   3. Observe the upper display. Check that the diagnostic code is showing.

   4. If the diagnostic code is not showing, enter the service mode. View the fault log (OP1). Check that the diagnostic code is showing.

      Expected Result: A CID 441 FMI 12 is showing as a active fault or an inactive fault.

      Results:

      • No - A CID 441 FMI 12 has not occurred. STOP.

      • Yes - A CID 441 FMI 12 is active or inactive. Proceed to 2.

2. Check internal cable of relay module.

   Note: Only open the relay module in a dry environment. If the inspection takes more than twenty minutes replace the desiccant bag in the GSC housing. See Testing And Adjusting, "Relay Module - Replace".

   1. Turn the ECS to OFF/RESET.

   2. Temporarily, remove the relay module from the GSC. See Testing And Adjusting, "Relay Module - Replace".

   3. Check the cable that attaches the relay module to the GSC.

      Expected Result: The cable should be firmly seated in the connector. The clamp should be in place. The cable should not be damaged.

      Results:

      • OK - Reassemble the relay module to the GSC. Proceed to 3.

      • NOT OK - Replace the connector clamp if it is missing. If the cable is damaged, replace the GSC. STOP.

3. Perform a functional check for the OSR.

   1. Turn the ECS to OFF/RESET.

   2. Disconnect all wires from RM-13 and RM-14 of the relay module.

   3. At the relay module, measure the resistance from RM-13 to RM-14. Resistance should be greater than 5000 ohms.

   4. Start the engine. Make sure that the engine oil pressure is greater than the setpoint for low oil pressure shutdown at idle speed (P14).

   5. At the relay module, measure the resistance from RM-13 to RM-14. Resistance should be less than 5 ohms.

      Expected Result: For 3.c, the resistance should be greater than 5000 ohms. For 3.e, the resistance should be less than 5 ohms.

      Results:

      • OK - It is likely that a temporary bad electrical connection existed and this troubleshooting procedure corrected it. Check the electrical connectors, terminals and wiring. See Testing And Adjusting, "Electrical Connector - Inspect". STOP.

      • NOT OK - Either one of the resistance measurements are NOT correct. The relay module is faulty. Replace the relay module. See Testing And Adjusting, "Relay Module - Replace". STOP.