840493T 1 Mercruiser COWL ASSEMBLY, Transom

Illustration 1 g01509833
Schematic for the Crank Without Injection switch
Illustration 2 g01509835
A typical view of the P1 connector (harness side) pin locations.
(35) Switch return
(46) Crank without inject (N/O)
(47) Crank without inject (N/C) Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J1/P1 ECM connectors and the connectors for the engine shutdown switch. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires for the engine shutdown switch.
Check the torque of the allen head screw on the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and the wiring for abrasion and for pinch points from the switch back to the ECM. Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and the connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a fault in the connectors and/or wiring.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.If necessary, use the electronic service tool to perform a "Wiggle Test".Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the electronic service tool to the diagnostic connector.
Restore the electrical power to the ECM.
Toggle the engine shutdown switch and monitor the electronic service tool for the active diagnostic code. Wait at least 30 seconds so that any codes may become active.
Remove the electrical power from the ECM. Expected Result:A diagnostic code is not active.Results:
OK - The code does not become active.Repair: The switch is operating normally. There may be an intermittent fault in the wiring harness or in a connector. Check the wiring harness and the connectors for an intermittent electrical fault. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A diagnostic code is active. Proceed to Test Step 3.Test Step 3. Check the Resistance of the Switch Circuit at the ECM Connector
Disconnect the J1/P1 connector. Note: Wiggle the harnesses during the following measurements in order to detect any intermittent faults.
Measure the resistance between terminals P1-35 (return) and P1-47 (Crank without inject (N/C)). The correct resistance measurement indicates a short circuit.
Measure the resistance between terminals P1-35 (return) and P1-46 (Crank without inject (N/O)). The correct resistance measurement indicates a open circuit.
Toggle the engine shutdown switch to the STOP position.
Measure the resistance between terminals P1-35 (return) and P1-46 (Crank without inject (N/C)). The correct resistance measurement indicates a open circuit.
Measure the resistance between terminals P1-35 (return) and P1-47 (Crank without inject (N/O)). The correct resistance measurement indicates a short circuit.
Connect the J1/P1 connectors. Expected Result:The resistance measurements are within the specifications.Results:
OK - All of the resistance measurements are within the specifications.Repair: Perform the following procedure:
Restore the electrical power to the ECM.
Use the electronic service tool to check for the active code again. Toggle the engine shutdown switch and check for the code. Also, wiggle the switch harness from the switch to the ECM in order to reveal an intermittent fault. If the code does not recur, the fault is resolved. The original fault was probably caused by a poor electrical connection.If the code recurs, the ECM is not detecting the switch inputs correctly. Perform the following procedure:
Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".
Use the electronic service tool to check for active diagnostic codes.
If a diagnostic code is still active, contact the technical communicator at a Caterpillar dealer. Note: This consultation can greatly reduce the repair time.
If necessary, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".
Use the electronic service tool to verify that the fault is eliminated.
If the fault is eliminated with the test ECM, reconnect the suspect ECM. Verify that the active diagnostic code returns.
If the active diagnostic code returns with the suspect ECM, replace the ECM. STOP
Not OK - At least one of the resistance measurements is not within specifications. There is a fault in the switch or in a harness. Proceed to Test Step 4.Test Step 4. Check the Operation of the Crank Without Injection Switch
Disconnect the connectors for the crank without injection switch.
Place the crank without injection switch in the Crank with Injection position.
Measure the resistance between terminals 2(return) and 3(Crank without Inject (N/O)). The correct resistance measurement indicates an open circuit.
Measure the resistance between terminals 1 (Crank without Inject (N/C)) and 2 (return). The correct resistance measurement indicates a short circuit.
Toggle the crank without injection switch to the Crank without Injection position.
Measure the resistance between 1 (Crank without Inject (N/C)) and 2 (return). The correct resistance measurement indicates an open circuit.
Measure the resistance between 2 (return) and 1 (Crank without Inject (N/O)). The correct resistance measurement indicates a short circuit. Expected Result:The resistance measurements are within the specifications.Results:
OK - All of the resistance measurements are within the specifications.Repair: The switch is OK. There is a fault in the wiring harness or the connectors. Check the machine wiring harnesses and the connectors for an open circuit or a short circuit. Repair the wiring and/or the connectors. Replace parts, if necessary. Refer to Troubleshooting, "Electrical Connectors - Inspect".Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.STOP
Not OK - At least one of the resistance measurements is not within specifications. There is a fault with the switch. Replace the switch. Verify that the fault is eliminated.