956157 Mercruiser VALVE, INLET (STANDARD)

The following background information is related to this procedure:The ECM supplies regulated +5 VDC to the following sensors on the J2 connector (a 3509-2 diagnostic code applies to the 5 VDC supply for these sensors) :
The position sensor for the intake throttle valve
The position sensor for the NOx Reduction System (NRS) valve
The intake manifold air pressure sensor
The fuel rail pressure sensor
The exhaust gas pressure sensor
The secondary (camshaft) speed/timing sensorThe ECM supplies regulated +5 VDC to the following sensors on the J1connector (a 3510-2 diagnostic code applies to the 5 VDC supply for these sensors) :
The Diesel Particulate Filter (DPF) differential pressure sensor
Analog throttle position sensor 1The ECM supplies regulated +5 VDC to analog throttle position sensor 2 on the J1 connector. A 3511-2 diagnostic code applies to the 5 VDC supply for this sensor.
Illustration 1 g06555147
Schematic diagram of the 5 VDC supply circuit supplied by the J2 connector.
Not all connectors are shown. Refer to the appropriate Electrical Schematic.
Illustration 2 g03775432
Typical example of the 5 VDC supply circuit supplied by the J1 connector. A 3510-2 diagnostic code applies to the 5 VDC supply in this illustration.
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 3 g03775446
Typical example of the 5 VDC supply circuit supplied by the J1 connector. A 3511-2 diagnostic code applies to the 5 VDC supply in this illustration.
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 4 g02727977
Typical view of the pin locations on the J2 connector for the 5 VDC supply.
(8) Intake throttle valve position sensor 5 VDC supply
(9) NRS valve position sensor 5 VDC supply
(10) Intake manifold air pressure sensor 5 VDC supply
(11) Fuel rail pressure sensor 5 VDC supply
(12) Exhaust gas pressure sensor 5 VDC supply
(13) Secondary (camshaft) speed/timing sensor 5 VDC supply
(24) NRS valve position sensor ground
(25) Intake manifold air pressure sensor
(26) Fuel rail pressure sensor ground
(27) Exhaust gas pressure sensor ground
(28) Secondary (camshaft) speed/timing sensor ground
(37) Intake throttle valve position sensor ground
Illustration 5 g02728012
Typical view of the pin locations on the P1 connector for the 5 VDC supply
(14) DPF differential pressure sensor 5 VDC supply
(16) Analog throttle position sensor (1) 5 VDC supply
(17) Analog throttle position sensor (2) 5 VDC supply
(36) DPF differential pressure sensor ground
(38) Analog throttle position sensor (1) ground
(39) Analog throttle position sensor (2) ground
Table 2
Troubleshooting Test Steps Values Results
1. Determine the Code
A. Connect the electronic service tool to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Turn the keyswitch to the ON position.
C. Check if one of the diagnostic codes listed in Table 1 is active or logged.
Diagnostic Codes
Result: A -2 diagnostic code is active.
Note which 5 V supply is reporting the active sensor supply code.
Proceed to Test Step 2.
Result: A -2 diagnostic code is logged.
An intermittent fault may be present. Refer to Troubleshooting, "Electrical Connectors - Inspect" in order to identify intermittent faults.
2. Check for a Failed Sensor
A. Connect to the electronic service tool.
B. Turn the keyswitch to the ON position.
C. Disconnect a sensor on the suspect sensor supply circuit.
D. Monitor the electronic service tool while the sensor is disconnected to see if the active code changes to logged.
E. Connect the suspect sensor to the wiring harness
F. Repeat steps C through E for each sensor on the suspect sensor supply.
Failed Sensor
Result: The suspect sensor supply active code changes to logged when a sensor is unplugged.
Repair: Replace the failed sensor.
Verify that the repair resolved the problem.
Result: The suspect sensor supply active code remains active after all sensors on the sensor supply circuit have been checked.
Repair: The fault is in the wiring harness.
Check all wiring on the suspect sensor supply. Refer to the appropriate Electrical Schematic.
Replace the faulty wiring.
If the procedure did not correct the fault, contact the Dealer Solution Network (DSN).