Help Transmission reading zero on DDEC???

[Hat52MY]

Have a pair of 8v92TA with DDECs attached to Twin Disc MG-5111 Deep Case (DD 5111V DC) marine gears. These engines are Electronically controlled with Electronic Control Modules (ECMs) for both Engine, Gears & Controls.

Issue: Starboard gear pressure reading 0 PSI but transmission works as normal

Trouble Shooting to date:
- Oil pressure sending unit (Detroit Diesel Part #: 23520795 (Transducer)) cleared of issue. Swapped out and tested on Port main gear and pressures reads as normal.
- Placed Port Main gear sending unit on Starboard Gear and reading 0, but transmission works as normal
- Connected manual pressure gauge directly to Starboard Gear and pressures read as normal
- Tested three wires from ECM to Starboard transducer:
○ Wire Sensor power supply 5vDC - Checked out w/5 volts
○ Wire Sensor Return - Not sure how to test thoughts??, same OHMs reading as port engine
○ Wire Pump pressure sensor - Not sure how to test thoughts??, same OHMs reading as port engine
○ Ground appears good from transducer to engine block
- Checked for obvious loose wires to the Eltreic Control Module (ECM) and all appears normal.
- Need additional suggestions to trouble shoot and diagnose....help!!!

[Hat52MY]

Is it possible there is an associated fuse of breaker associated with tranmission pressure? This one has me truly puzzeled. I'm sure with the collective knowledge on the Forum we can bring this one to resolution. Any and all thoughts are welcomed.

[Dan Mapes]

Did you measure the sensor voltages back at the ECM with the engine running? Is it possible to pull the plug for the sensor and see what the reading is? If it is also zero there must be an open somewhere. It could be at any of the connectors or their interface (solder connection) to a circuit board. If you wiggle the connector with the engine running at the ECM does the value change?

[Hat52MY]

Appreciate the ideas Dan. I will have to make up a temporary harness to complete the test. Will also try the other items too. I am also going to see if there is any applicable fuse. Had rental car one time that the electronic odometer was not working, just displayed "0". It turned out the fuse had blown, possibly something similar. Hope to give it another go this weekend.

[Dan Mapes]

Some times you can poke a wire through the insulation. The only problem is making sure you seal it up again real good with something like liquid tape. If you cut strip and test you can always just splice it and seal it up good. It all depends on how the wire harness is put together.

[Hat52MY]

It appears this was only a loose wire connection. Pressure reading now displaying properly on DDEC.