atoner

While under the hood with the engine cover off looking for a ticking noise, I noticed a frayed wire running under the exhaust duct near the oil cooler.



Through the self-study programme PDF, I tracked the cable down to the oil thermostat and oil pressure switch.

I haven't gotten any related DTCs or a MIL, and it looks like the oil thermostat wires are intact but the oil pressure switch wire is just hanging on my a single strand.

It initially looked to me like there was some missing or defective insulation since the damage it worst right under the duct. I'm thinking the heat just gradually degraded the insulation.
I've also seen mention of rodent damage, in general terms but not specially about this issue. I have personally seen rodent damage on another vehicle's wiring. I don't see any other evidence of chewing around my engine. There's a nice boot over the oil pressure switch that's still intact.

I'm wondering a few things:

1. What happens if I loose that last strand on the oil pressure switch? The PDF says it "indicates to the engine control unit whether the spray jet valve has been closed." The PDF also seems to indicate that the oil pressure pushes against a spring to open the valve and spray the piston crowns. So the sensor just lets the PCM know if the crowns are being sprayed but doesn't have active control over them. Hopefully it is just a DTC if the wire goes out.
2. Any thoughts on what could have caused this? Defect vs. rodent vs. something else?
3. I'm still in warranty and will have a dealer look at it along with the noise. Is a proper fix a new wiring harness or just a splice with proper insulation? I lost track of the cable at the front of the engine.

Thanks.

rhranac

While it’s difficult to tell for certain from the photos, my vote is rodent damage. The latter is no fun, and can be expensive. In the 2019 timeframe a squirrel got under the hood of my 2013 Toyota Tundra and did extensive damage to the wiring harness (the wiring used soy-based insulation, which is common in modern vehicles). The repair cost was nearly $5000, in large part because of the labor. Not only did the underhood harness have to be replaced, so did some of the harness under the dash, which required dash removal to access. After the second wiring harness was damaged by a squirrel or squirrels, resulting in an almost $5k repair (again), I sold the truck. Same kind of damage happened to my next door neighbor, who at the time was a state trooper. He went outside one morning to start his patrol car and head for work. It didn’t start, and was towed to a dealer used by the state for repair. The culprit was a squirrel, which was still under the hood (!!) at the dealership, and ran off shortly after the hood was opened.