879288T26 Mercruiser HARNESS ASSEMBLY

If the application is equipped with two throttles, the engine will use the second throttle until the fault is repaired.If a second throttle is not installed or if the second throttle has a fault, the following conditions will occur:
The engine will default to limp home mode.
If the engine speed is higher than the speed in limp home mode, the engine will decelerate to limp home mode.
If the engine speed is lower than the speed in limp home mode, the engine speed will remain at the current speed.
The engine will remain at this speed while the diagnostic code remains active.
All inputs from the faulty throttle are ignored by the ECM until the fault is repaired.
All inputs from the repaired throttle will be ignored by the ECM until the keyswitch has been cycled.The IVS may be installed. The IVS is required for mobile applications. The IVS is part of the throttle position sensor. The IVS is CLOSED when the low idle is set.The configuration parameters for the throttle and for the IVS thresholds are programmed into the ECM. Use the electronic service tool in order to display the configuration parameters for the throttle and for the IVS.If the IVS operates outside of the programmed range, then the engine speed may not respond to changes in the throttle position.The electronic service tool may be used for the following:
If necessary, reset the IVS threshold for an existing IVS.
If necessary, view the IVS change point and reset the IVS thresholds when a new throttle assembly is installed.
Illustration 1 g03771038
Schematic diagram for the Idle Validation Switch (IVS) switch circuit
Illustration 2 g03771057
View of the pin locations on the P1 connector for the IVS circuit
(42) IVS 2
(76) IVS 1
Table 2
Troubleshooting Test Steps Values Results
1. Check for Active Diagnostic Codes
A. Establish communication between the electronic service tool and the ECM. Refer to Troubleshooting, "Electronic Service Tools"
B. Check for active or logged codes.
Diagnostic Trouble Codes
Result: There is an active or logged , 558-2 or 2970-2 diagnostic code.
Proceed to Test Step 2.
2. Check the Operation of the IVS
A. Turn the keyswitch to the OFF position.
B. Connect the electronic