865440H73 Mercruiser HOUSING ASSEMBLY, Driveshaft - Complete (16/19)

Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
617-5 Air Inlet Heater Relay open/current below normal The Electronic Control Module (ECM) detects a current flow that is below normal during an attempt to energize the air inlet heater relay. The code is latched. The code is logged.
The air inlet heater will be energized continuously.
617-6 Air Inlet Heater Relay grounded/current above norm The ECM detects excessive current during an attempt to energize the air inlet heater relay. The code is latched. The code is logged.
The air inlet heater will be disabled.
The engine may experience hard starting and/or the engine may emit excessive white smoke. The air inlet heater improves the engine's ability to start when the engine is cold. A reduction of white smoke is also a benefit of the air inlet heater.The ECM activates the air inlet heater via the air inlet heater relay. The air inlet heater is activated according to the following cycles:
Power up cycle
Preheat cycle
Crank cycle
Running cycle
Postheat cyclePower Up Cycle - The ECM activates the air inlet heater for two seconds after the ECM is first powered up regardless of temperature or engine speed.Preheat Cycle - If the coolant temperature is less than 49 °C (120 °F), the ECM activates the air inlet heater for 30 seconds. If the operator attempts to start the engine before the end of the preheat cycle, the ECM will begin using the strategy for the crank cycle.Crank Cycle - When the engine is cranking and the coolant temperature is less than 49 °C (120 °F), the air inlet heater will remain on while the engine is cranking. If the engine fails to start, the ECM will revert to the preheat cycle.Running Cycle - The air inlet heater will remain on after the engine has started. If the coolant temperature does not reach 49 °C (120 °F) within five minutes, the ECM will use the postheat cycle.Postheat Cycle - The air inlet heater will cycle on and off if the coolant temperature is still less than 49 °C (120 °F). The heater will turn on for 30 seconds. Then, the heater will turn off for 10 seconds. This cycle continues for 15 minutes. The cycle ends if the coolant temperature exceeds 49 °C (120 °F).
Illustration 1 g01338166
Schematic for the air inlet heater
There is a fuse for the air inlet heater between the starting motor and the air inlet heater relay. Also, the heating element is grounded with a braided ground strap. Check the condition of these components prior to troubleshooting a problem with the air inlet heater.Test Step 1. INSPECT THE ELECTRICAL CONNECTORS AND THE WIRING
Turn the keyswitch to the OFF position.
Illustration 2 g01338263
Typical left side engine view
(1) Air inlet heater relay
(2) Connector for the air inlet heater relay
(3) Air inlet heater
(4) J2/P2 ECM connectors
(5) In-line fuse for the air inlet heater
Thoroughly inspect all of the connections for components (1), (3), and (5). Also, thoroughly inspect connectors (2) and (4). Check the condition of the in-line fuse (5). Ensure that the fuse is not blown. Check that the connections for the fuse holder are free of corrosion and moisture. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01338283
Terminal locations at the P2 ECM connector for the air inlet heater
(P2-5) Air inlet heater
(P2-79) Return for the air inlet heater
Illustration 4 g01155187
Terminal locations at the connector for the air inlet heater
(Terminal 1) Air inlet heater
(Terminal 2) Return for the air inlet heater
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the air inlet heater.
Check the allen head screw for each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasion and for pinch points from the air inlet heater back to the ECM and from the air inlet heater back to the battery. Expected Result:All 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 connectors appear to be OK. Proceed to Test Step 2.
Not OK - A problem has been found with a connector and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. CHECK FOR ACTIVE DIAGNOSTIC CODES
Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Turn the keyswitch to the ON position.
Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for these codes:
617-5
617-6
Turn the keyswitch to the OFF position. Expected Result:No diagnostic codes are active for the air inlet heater.Results:
OK - Neither of the above codes are active. There may be a problem with the secondary circuit for the air inlet heater. Proceed to Test Step 5.
Not OK - At least one of the codes that are listed above are active. A 617-5 or 617-6 diagnostic code is active. There is a problem in the control circuit for the air inlet heater. Proceed to Test Step 3.Test Step 3. CHECK FOR A CONTROL INPUT VOLTAGE AT THE RELAY
Illustration 5 g01118589
Small terminals for the typical air inlet heater relay
Disconnect the wires from the small terminals of the air inlet heater relay.
Install a test lamp across the wires.
Turn the keyswitch to the ON position.
Start the "Air Inlet Heater Override" on Cat ET and observe the test lamp. Note: Do not leave the "Air Inlet Heater Override" on for an extended period of time. This will prevent unnecessary cycling of the air inlet heater and the battery from discharging. The "Air Inlet Heater Override" has a one minute timer that disables the test when the time expires.
Stop the "Air Inlet Heater Override".
Turn the keyswitch to the OFF position. Expected Result:The test lamp i