90949T Mercruiser TUBE, Exhaust

The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Illustration 1 g01131276
Diagram for the installation of a connector plug (typical example)
(1) ECM connector
(2) Correctly inserted plug
(3) Incorrectly inserted plug
Illustration 2 g01131019
Seal for a three-pin connector (typical example)
Illustration 3 g01883953
Leaky seal at the connector (typical example)
Some components are not shown for clarity.
(1) Wire pulled to one side. Note the gap between the seal and the wire.
Table 1
Troubleshooting Test Steps Values Results
1. Check Connectors for Moisture and Corrosion
A. Inspect all the harnesses. Ensure that the routing of the wiring harness allows the wires to enter the face of each connector at a perpendicular angle. Otherwise, the wire will deform the seal bore. This situation can create a path for the entrance of moisture. Verify that the seals for the wires are sealing correctly.
B. Ensure that the sealing plugs are in place. If any of the plugs are missing, replace the plug. Ensure that the plugs are inserted correctly into the connector. Refer to Illustration 1.
C. Disconnect the suspect connector and inspect the connector seal. Ensure that the seal is in good condition. If necessary, replace the connector.
D. Thoroughly inspect the connectors for evidence of moisture entry.
Note: Some minor seal abrasion on connector seals is normal. Minor seal abrasion will not allow the entry of moisture.
If moisture or corrosion is evident in the connector, the source of the moisture entry must be found and repaired. If the source of the moisture entry is not repaired, the fault will recur. Simply drying the connector will not rectify the fault. Check the following items for the possible moisture entry path:
Missing seals
Incorrectly installed seals
Nicks in exposed insulation
Improperly mated connectors
Moisture can also travel to a connector inside a wire. If moisture is found in a connector, thoroughly check the connector harness for damage. Also check other connectors that share the harness for moisture.
Note: The ECM is a sealed unit. If moisture is found in an ECM connector, the ECM is not the source of the moisture. Do not replace the ECM.
E. Check the connectors for white deposits. White deposits may indicate that the connector has been contaminated with Diesel Exhaust Fluid (DEF).
DEF may corrode the copper wire in the wiring harness.
Harness, connectors, and seals are OK. Result: A fault has been found with the harness or the connectors.
Repair: Repair the connectors or the wiring, as required. Ensure that all the seals are correctly installed. Ensure that the connectors have been reattached.
If corrosion is evident on the pins, sockets or the connector, use only denatured alcohol to remove the corrosion. Use a cotton swab or a soft brush to remove the corrosion.
If moisture was found in the connectors, run the engine for several minutes and check again for moisture. If moisture reappears, the moisture is wicking into the connector. Even if the moisture entry path is repaired, replacement of the wires may be necessary.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The harness, connectors, and seals are in good condition.
Proceed to Test Step 2.
2. Check the Wires for Damage to the Insulation
A. Carefully inspect each wire for signs of abrasion, nicks, and cuts.
Inspect the wires for the following conditions:
Exposed insulation
Rubbing of a wire against the engine
Rubbing of a wire against a sharp edge
B. Check all the fasteners for the harness and the strain relief components on the ECM to verify that the harness is correctly secured. Also check all the fasteners to verify that the harness is not compressed. Pull back the harness sleeves to check for a flattened portion of wire. A fastener that has been overtightened flattens the harness. This condition damages the wires that are inside the harness.
The wiring is OK
Result: There is damage to the harness.
Repair: Replace the harness.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The wires are free of abrasion, nicks, and cuts and the harness is correctly clamped.
Proceed to Test Step 3.
3. Inspect the Connector Terminals
Note: The ECM connectors cannot be repaired. If damage is found on an ECM connector, the harness must be replaced.
A. Visually inspect each terminal in the connector. Verify that the terminals are not damaged. Verify that the terminals are correctly aligned in the connector and verify that the terminals are correctly located in the connector.
Terminals are aligned and undamaged
Result: The terminals of the connector are damaged.
Repair: Repair the terminals and/or replace the terminals, as required.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The terminals are OK.
Proceed to Test Step 4.
Illustration 4 g01802454