Trim Position Sensor Troubleshooting; Trim Position Sensor; Troubleshooting The Trim Position Circuit - Mercury V6 175 Diagnostic Manual

Advanced Midsection (AMS) Power Trim
If the motor will not run in the up direction, it may be either the up relay is not making contact to 12 volts or the down relay is not
making contact to ground. The opposite is true if the system will not run down. When the system is not energized, both relays
should connect the heavy trim motor leads to ground.
To test which relay is faulty if the trim system does not operate in one direction:
1. Remove the starboard intake plenum. Refer to the appropriate service manual for instructions.
2. Remove the relay from the bracket.
3. Partially remove the relay from the connector just far enough to reach the electrical contacts with the voltmeter lead.
4. Check for continuity between the heavy leads from the trim relays to ground.
DMT 2004 Digital Multimeter
Meter Test Leads
Red
Green
Blue
5. Replace the relay that does not have continuity.
6. Connect a voltmeter to the heavy blue lead and to ground. There should be 12 volts on the blue lead when the up switch is
pushed and 12 volts on the green lead when the down switch is pushed. Replace the relay that does not switch the lead to
positive.
7. Install the starboard intake plenum. Refer to the appropriate service manual for instructions.

Trim Position Sensor Troubleshooting

Trim Position Sensor

The trim position sensor (TPS) is located on the bottom of the mount cradle. It supplies the propulsion control module (PCM)
with trim position information. The PCM will generate and store a failure code when the TPS fails, and the alarm horn will
sound. The trim position sensor affects trim functions controlled by the helm trim switch and the cowl tilt switch.
With the engine running below 2000 RPM, the outboard can be tilted to any position in the trim range or the trailer range. If
above 2000 RPM, the trim range will be limited to prevent the outboard from reaching the trailer range. However, if you are
loading the boat onto the trailer for example, and tilt the outboard up into the trailer range while below 2000 RPM, the throttle
can be advanced to a maximum of 4400 RPM.
The following are some of the problems encountered with a faulty trim position sensor:
• Engine will trim higher than the set trim limit at speeds above 2000 RPM
• Engine trims past the maximum trailer limits
• Engine trims normally, but there are no trailer limits

Troubleshooting the Trim Position Circuit

Monitor the trim position sensor analog‑to‑digital counts (ADC) with the CDS G3. Verify wiring harness integrity with a DMT
2004 digital multimeter or equivalent.
CDS G3 Interface Kit
DMT 2004 Digital Multimeter
Page 6D-10
Black
Ground
Ground
© 2018 Mercury Marine
91‑892647A01
Meter Scale
Full continuity (R x 1) or Auto
Full continuity (R x 1) or Auto
8M0138392
91‑892647A01
Reading (Ω)
< 0.5 Ω
< 0.5 Ω
90-8M0146617 eng JULY 2018