Where Is The Oil Pressure Sender Connector On A Bobcat S175

[MikePhua]

Overview Of The Bobcat S175 And Its Engine Layout
The Bobcat S175 is one of the most widely recognized skid steer loaders in the 1,700 lb (770 kg) rated operating capacity class. Produced in the early to mid-2000s, it helped Bobcat maintain its strong market share in compact loaders, a segment where Bobcat has historically sold hundreds of thousands of units worldwide since the brand’s origin in the late 1950s. The S-series machines, including the S150, S160, S175, and S185, share a similar frame and engine bay layout, which is why many service procedures and component locations look alike across these models.
The S175 typically uses a 4-cylinder diesel engine (commonly a Kubota or similar compact industrial diesel, depending on production year). In this layout, most service points are grouped at the rear of the machine behind the swing-out tailgate and above or around the fuel filter and oil filter. Understanding this basic arrangement makes it much easier to locate small but important components such as the oil pressure sender and its electrical connector.
The oil pressure sender (or oil pressure sensor) is a device that converts engine oil pressure into an electrical signal. That signal is fed to the machine’s monitoring system, which drives warning lights, buzzers, or digital codes if pressure falls outside safe limits. If the connector is loose, damaged, or unplugged, the machine can throw fault codes or shut down to protect the engine, even if the actual oil pressure is fine.
What The Manual Means By Oil Pressure Sender Connector
When the service manual tells you to “check the oil pressure sender connector,” it is referring to the small two-wire or three-wire plug that clips onto the oil pressure sensor body. This connector supplies a reference voltage and ground to the sensor and carries the signal back to the controller.
For the operator or mechanic, checking the connector generally involves

• Making sure it is fully seated on the sensor
  
• Inspecting the plastic housing for cracks or broken locking tabs
  
• Looking for corrosion, pushed-back pins, or chafed wiring near the plug
  
• Confirming the wiring harness is supported and not rubbing on sharp edges or hot surfaces
  

Because compact skid steers route many wires through very tight spaces, it can be surprisingly easy for one connector to be pulled loose, especially during filter changes or cleaning.
Typical Location Of The Oil Pressure Sender On An S175
On the Bobcat S175, the engine oil pressure sender is mounted on the engine block, and its connector is usually found in the same general area as the fuel filter. Technicians familiar with this model often describe it as “above the fuel filter” on the side of the engine.
A practical way to find it step by step

• Open the tailgate and, if equipped, tilt the cab for better access according to the safety procedure in the manual
  
• Locate the engine oil filter and the fuel filter assembly at the rear/right side of the engine compartment (orientation can vary slightly by engine version)
  
• Look along the side of the engine block near the fuel filter head and oil galleries for a small threaded sensor body with an electrical plug attached
  
• The sensor is typically screwed into an oil gallery port pointing outward or slightly downward from the block
  
• The connector will be a small molded plug with one clip tab that snaps onto the end of the sensor
  

On many S-series Bobcats, the oil pressure sensor is not hidden deep inside the engine bay; instead, it sits where it can “see” main gallery pressure shortly after oil leaves the pump, which is why it tends to be near the oil filter housing or just above/near the fuel filter zone. That location gives an accurate picture of true engine lubrication pressure rather than just filter outlet pressure.
Recognizing The Oil Pressure Sender Among Other Sensors
Because modern skid steers combine several sensors in a compact engine bay, it helps to distinguish the oil pressure sender from nearby components.
You will typically see

• Oil pressure sender
  • Small cylindrical or hex-shaped metal body
    
  • Threaded base screwed into the block or oil gallery
    
  • One small electrical connector on the end
    
• Coolant temperature sensor
  • Often threaded into the cylinder head or thermostat housing
    
  • Near coolant hoses and water outlet
    
• Fuel pressure or fuel temperature sensor (if equipped)
  • Mounted on or near the fuel filter head
    
• Charge pressure or hydraulic pressure senders
  • Located on hydraulic manifolds, filter heads, or pump housings, not on the engine block
    

The oil pressure sender’s key visual clue is that it is directly in an oil passage on the engine, not on a coolant or hydraulic housing. On an S175, once you identify the fuel filter and glance slightly above and on the engine side, that small threaded sensor with its plug is very likely your target.
Why The Connector Causes Warning Codes And Shutdowns
The S175’s monitoring system watches oil pressure closely. If the sensor signal drops below a threshold or the controller detects an open circuit, it interprets this as low or lost oil pressure. Depending on software version and settings, the machine may

• Illuminate a low oil pressure warning icon
  
• Trigger an audible alarm
  
• Log an error code related to oil pressure
  
• Reduce engine power or even shut down after a timed delay to protect the engine
  

Real-world examples from similar skid steer models show that

• A loose connector can cause intermittent fault codes even when actual oil pressure is stable at 50–55 psi at full throttle
  
• Broken or corroded pins can mimic a genuine low-pressure fault and cause unnecessary shutdowns
  
• Replacing the sensor without fixing a damaged connector or harness can give only temporary relief before the problem returns
  

This is why the manual specifically instructs owners to “check the oil pressure sender connector” as one of the first diagnostic steps.
Practical Inspection Routine For The Connector
A simple and effective inspection routine on a Bobcat S175 might look like this

• Prepare the machine
  • Park on level ground
    
  • Lower the lift arms and attachment to the ground
    
  • Engage the parking brake and shut off the engine
    
  • Disconnect the battery if you will be working around the harness for an extended period
    
• Access the sensor area
  • Open the tailgate
    
  • Tilt the cab if needed for more room
    
  • Use a good work light to see above and around the fuel filter
    
• Inspect the connector
  • Locate the small sensor threaded into the block above or near the fuel filter area
    
  • Identify its plug, then press the locking tab and gently unplug it
    
  • Check the connector shell for cracks, missing locking tab, or melted sections
    
  • Look closely at the pins or sockets for green corrosion, rust, or bent terminals
    
• Clean and reseat
  • Use electrical contact cleaner rated for automotive use to clean the terminals
    
  • Let it dry fully
    
  • Apply a thin layer of dielectric grease around (not inside) the terminal area if appropriate for your climate
    
  • Plug the connector back on firmly until the locking tab clicks
    
• Check the harness
  • Follow the wire a short distance along the harness
    
  • Look for spots where it has rubbed against brackets, hoses, or sharp edges
    
  • Secure loose sections with proper loom and ties to prevent future wear
    

After this, start the machine and run it while monitoring the panel. If the fault does not return, you may have solved a purely electrical connection issue.
When To Suspect The Sensor Versus Real Low Pressure
If warning codes persist after confirming the connector is sound, you need to decide whether the sensor itself is faulty or the engine genuinely has low oil pressure.
Basic decision steps

• Verify oil level
  • Make sure engine oil is at the correct level and of the proper grade
    
• Listen and observe
  • An engine with true low oil pressure may have noisy lifters or bearings, especially at hot idle
    
• Mechanical gauge test
  • Install a temporary mechanical oil pressure gauge in place of, or tee’d into, the sender port
    
  • Run the engine to operating temperature and record pressure at idle and high idle
    

Typical healthy diesel engines of this size often show

• Around 20–30 psi at hot idle
  
• Around 50–60 psi at high idle under normal conditions
  

Exact values depend on the engine manufacturer’s specification, but if your mechanical gauge shows stable pressure in that general range while the electronic system reports low pressure, the sensor or its wiring is the more likely culprit.
Bobcat As A Brand And The Evolution Of Its Monitoring Systems
Bobcat, founded in North Dakota in the late 1950s, pioneered the modern skid steer loader and has produced several hundred thousand machines across many generations. Over time, the company has steadily added more sensors and automated protections to reduce catastrophic failures.
On older mechanical machines, a simple pressure switch turned on a warning light when oil pressure dropped below a threshold. Later models, including the S175, use pressure senders that provide analog signals. The controller interprets these signals to generate more nuanced warnings and fault codes, making better decisions about when to protect the engine with derates or shutdowns.
Industry data from equipment warranty programs indicates that electronics and sensor issues are now among the most common categories of service calls. A significant portion of those issues come down to loose connectors, chafed wires, or minor corrosion rather than failed mechanical components. This makes basic connector inspection an essential skill for any owner or mechanic, especially on widely used models like the S175, which are still found on farms, construction sites, and rental fleets long after production ended.
Common Mistakes When Working Around The Sender
Owners new to the Bobcat S175 often make a few predictable mistakes when dealing with the oil pressure sender and its connector

• Confusing the oil pressure sender with another sensor
  • For example, unplugging a temperature sender or a hydraulic pressure sender by mistake and creating additional warning codes
    
• Pulling on wires instead of the connector body
  • This can break internal crimp joints or loosen terminals
    
• Cross-threading or overtightening the sender
  • The port is usually in an aluminum or cast iron housing; improper torque can damage threads or crack the housing
    
• Neglecting to support the harness
  • After working around the engine, they leave the harness hanging loose, which later rubs through on a bracket or engine cover
    

Avoiding these errors is mostly a matter of patience and taking a few extra minutes to identify parts correctly and handle connectors with care.
A Short Story From The Field
A small landscaping company bought a used Bobcat S175 with around 3,200 hours. Within a week, the operator reported that the machine would occasionally beep and flash a low oil pressure warning at idle, even though the engine sounded fine. Worried about a major engine problem, the owner called a mobile mechanic.
The mechanic opened the tailgate, shined a light above the fuel filter, and found the oil pressure sender connector barely hanging on. At some point, during a fuel filter change or pressure washing, the plug had been tugged enough to weaken the locking tab. At idle, vibration made it lose contact for a split second, which the controller interpreted as a low pressure event.
The fix was simple

• Replace the worn connector shell
  
• Clean the terminals
  
• Clip it back firmly and secure the short harness section with a new clamp
  

The total repair took less than an hour and cost far less than replacing the sender or doing exploratory engine work. That experience convinced the owner to add “quick visual check of sensor connectors” to his regular maintenance routine, saving time and worry later.
Key Takeaways For Locating And Checking The S175 Oil Pressure Sender Connector
For anyone working on a Bobcat S175 and chasing oil pressure warnings, the essentials are straightforward

• Expect the oil pressure sender to be mounted on the engine block in an oil gallery, typically above or near the fuel filter area
  
• The “oil pressure sender connector” is the small electrical plug on the end of that sensor, and it must be firmly seated and clean to give reliable readings
  
• Always inspect the connector and nearby harness for damage, corrosion, and loose locking tabs before assuming the engine has a mechanical problem
  
• Use a mechanical gauge test to separate real low oil pressure from sensor or wiring faults when in doubt
  
• Handle connectors and senders carefully to avoid creating new issues while trying to fix existing ones
  

With a clear picture of where the sender sits and why its connector matters so much, S175 owners can tackle oil pressure warnings with more confidence and less guesswork, keeping a proven, widely used machine working reliably for many more hours.