815420 Mercury SHIFT SHAFT (X-LONG)

Illustration 1 g00531689
System Schematic For The Relay Driver Module (RDM) Data Link
The GSC+ communicates with the relay driver module (RDM) by a serial data link. When the data link malfunctions, R1 output (terminal 2 of the RDM) will be activated on and off at a rate of 0.5 Hz. Relays R2 through R9 may maintain the current state. Also, the relays may default to the OFF position. These steps are controlled by a jumper between terminals 6 and 7 of the RDM. If a jumper is NOT present when the serial data link has a fault, the relay outputs (R2 through R9) will maintain the states that the relays are currently in. If the jumper is present, R2 through R9 will default to OFF.Note: The maximum distance between a module and the GSC+ is 305 m (1000 ft). If this specification is not met, the data link may malfunction. The GSC+ may show a CID 475. If the distance is not in compliance with the specification, shorten the distance between the RDM and the GSC+.The possible cause of a CID 0475 FMI 03 is a short to the battery positive terminal.The GSC+ is not able to detect an open circuit condition of the relay driver module (RDM) data link. Clear the diagnostic code from the fault log after the troubleshooting is complete.Test Step 1. CHECK THE VOLTAGE OF THE DATA SIGNAL.
At the RDM, measure the DC voltage from terminal 4 (positive meter lead) to terminal 7 (negative meter lead). Expected Result:The voltage will vary from 0 DCV to 10 DCV.Results:
OK - The voltage varies from 0 DCV to 10 DCV. The voltage is correct. Proceed to test step 4.
NOT OK - The voltage does NOT vary from 0 DCV to 10 DCV. The voltage is NOT correct. Proceed to test step 2.Test Step 2. CHECK THE VOLTAGE OF THE RDM.
At the RDM, disconnect all wires from terminal 4.
Disconnect the harness connector from the GSC+.
At the RDM, measure the DC voltage from terminal 4 (positive meter lead) to terminal 7 (negative meter lead). Expected Result:The voltage is 11.6 0.5 DCV. Results:
OK - The voltage is 11.6 0.5 DCV. The voltage is correct. Proceed to test step 3.
NOT OK - The voltage is NOT 11.6 0.5 DCV. The voltage at the RDM is NOT correct. Repair: Replace the RDM.STOPTest Step 3. CHECK THE VOLTAGE OF THE GSC+.
All wires from terminal 4 of the RDM remain disconnected.
The harness connector from the GSC+ remains disconnected.
Measure the DC voltage from contact 30 of the GSC+ to the battery negative terminal of the relay module. The relay module is located on the rear of the GSC+. Expected Result:The voltage varies between 0 DCV to 5.5 DCV.Results:
OK - The voltage varies between 0 DCV to 5.5 DCV. The voltage is correct. Proceed to test step 4.
NOT OK - The voltage does NOT vary between 0 DCV to 5.5 DCV. The voltage is NOT correct.Repair: The GSC+ may have failed. It is unlikely that the GSC+ has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace". STOPTest Step 4. CHECK FOR A "B+" SHORT IN THE HARNESS.
All wires from terminal 4 of the RDM remain disconnected.
The harness connector from the GSC+ remains disconnected.
Measure the resistance from the wires of terminal 4 at the RDM to + battery of the relay module. The relay module is located on the rear of the GSC+.
Measure the resistance from the wires of terminal 4 at the RDM to battery negative of the relay module. The relay module is located on the rear of the GSC+. Expected Result:The resistance measurements should be greater than 20000 ohms.Results:
OK - Both the resistance measurements are correct. Repair: Check the electrical connectors, terminals and wiring. See Testing And Adjusting, "Electrical Connector - Inspect". If the failure still exists after the inspection, replace the RDM. STOP
NOT OK - Either one or both of the resistance measurements are NOT correct. The harness wiring with the incorrect measurement for resistance is shorted. Repair: Troubleshoot and repair the failed harness wiring between the RDM and the GSC+. See the preceding System Schematic.STOP