Mercury V6 175 Diagnostic Manual page 195

a - Shift actuator harness (8M0150597)
b - Engine harness
c - Shift actuator and wiring
d - Shift position sensor 2
e - Sensor power A
1. Insert the Y‑harness between the shift actuator and the engine harness.
Shift Actuator Harness
2. Connect a test light across the red/purple and black wires of the Y‑harness. Also connect a DMT 2004 digital multimeter
black lead to the black wire and red lead to the red/purple wire.
Test Light
DMT 2004 Digital Multimeter
3. Perform the indicated actions and use the test light to interpret the PCM shift actuator driver output.
NOTE: The engine will not shift into forward gear unless it is running.
Action
Neutral
Neutral to forward
Forward to neutral
Neutral to reverse
Reverse to neutral
Engine power up
4. If the light functions as expected, the PCM H‑bridge and actuation wires are operating correctly. Replace the shift actuator
after confirming that the gearcase is mechanically sound.
Shift Position Sensor Circuit Test
The Y‑harness may be used to break out the shift position sensor circuits for testing purposes. Connect a DMT 2004 digital
multimeter black lead to the sensor ground wire (black/orange) and the red meter lead to the wire as indicated in the table
below.
NOTE: The engine will not shift into forward gear unless it is running.
DMT 2004 Digital Multimeter
Shift Position Sensor Voltages
Shift Actuator Position
Neutral
Forward
Reverse
If the 5.0 volt reference voltage is present at sensor power A, but either position sensor feedback voltage is outside of the range
for the specified shift position, replace the shift actuator. The shift position sensors are not individually serviceable components.
90-8M0146617 eng JULY 2018
f -
g -
h -
i -
j -
Expected Test Light Pattern
No light
Light on for one second
Light on for one second
Light on for one second
Light on for one second
No light
Sensor power A (purple/yellow)
5.0 V
5.0 V
5.0 V
© 2018 Mercury Marine
H‑bridge (+)
Shift position sensor 1
H‑bridge (–)
Sensor power ground
Test light
8M0150597
Obtain locally
91‑892647A01
Measured voltage
91‑892647A01
Red Meter Lead Location
Sensor 1 (green)
2.271–2.686 V
3.662–4.712 V
0.293–1.343 V
Actuators and Relays
0
Positive (+)
Negative (–)
Negative (–)
Positive (+)
0
Sensor 2 (pink)
2.314–2.729 V
0.288–1.338 V
3.657–4.707 V
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