Bobcat D7518 (75-18) Fault Code: Right Swash Plate Not in Neutral
Also shown on the panel as 75-18 · Also called Drive Right Swash Plate Not in Neutral, Right Swash Plate Not In Neutral
Right Swash Plate Not in Neutral · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
D7518 (panel code 75-18) sets when the drive controller checks the right swash plate sensor at startup and finds it outside the neutral voltage range of 2.08 to 2.92 volts. This is a startup-only check, and when it fails the engine will shut down.
High severity. D7518 forces an engine shutdown when it sets, which stops the machine from being usable until the fault is cleared and the cause addressed. It is not an immediate safety emergency by itself, but an unresolved right swash plate sensor problem can affect drive control, so treat it as a stop-and-diagnose issue rather than something to run through.
What does Bobcat error code D7518 mean?
>This code is tied to the hydrostatic drive pump on the right side of the machine. Inside that pump, a swash plate controls the angle and direction of oil flow, which is what determines travel direction and speed. A sensor at the bottom of the pump is keyed to the swash plate and reports its position back to the drive controller.
At key-on with PTOL (the drive interlock/enable logic on Bobcat machines) enabled, the drive controller checks that this sensor reads within a defined neutral band. The sensor itself is supplied battery voltage from the gateway controller, and its full output signal range runs from 1.0 to 4.0 volts, but the neutral window the controller expects at startup is the narrower 2.08 to 2.92 volts. If the reading falls outside that window during this startup check, the controller sets D7518 and shuts the engine down.
Because this check only runs at system startup, and not during normal operation, the code will not appear mid-shift while driving. It shows up specifically when you try to start or restart the machine.
What triggers a Bobcat D7518 code?
D7518 sets when, at key switch or run/enter switch on with PTOL enabled, the drive controller reads the right swash plate sensor voltage outside the neutral range of 2.08 to 2.92 volts during the startup check. The sensor's full signal range is 1.0 to 4.0 volts, supplied with battery voltage from the gateway controller.
Common causes of D7518
- Contamination of the hydraulic system, which can affect pump and sensor operation.
- The hydraulic pump not being physically centered, so the swash plate is not actually in a true neutral position when checked.
- A fault in the right swash plate sensor itself.
- A fault in the drive controller.
- Moisture, corrosion, or pushed-back pins in the drive controller connectors, the swash plate sensor connector, or the SJC wire harness.
- Loose connections or a combination of wiring, connector, and controller issues, especially if the code shows up intermittently and is not present at the time of testing, in which case the root cause may not be found immediately.
How to troubleshoot Bobcat D7518: first checks
- Cycle the key switch off and back on, since power cycling is the listed step to clear the code once the repair is complete, and it also confirms whether the fault is still active.
- Inspect the drive controller connectors, the right swash plate sensor connector, and the SJC wire harness for moisture, corrosion, or pins that have been pushed back out of position.
- Check that all connections at the drive controller and swash plate sensor are seated tightly, since loose connections are a listed probable cause.
- Verify the hydraulic pump is physically centered as designed, since a pump that is off-center can prevent the swash plate from reading true neutral.
- Check the hydraulic system for contamination, which can affect pump behavior and sensor feedback.
- If the fault is intermittent and not present during testing, recheck wiring, connectors, and pins carefully rather than assuming the system is fine, since the cause may not show up until it fails again.
How the code clears
The listed method to clear D7518 once the repair is complete is to cycle power on the machine. No separate reset procedure or software step is listed beyond powering the key off and back on.
Affected models and serial ranges
D7518 appears in our records across 16 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-ATZC99999 |
| S530 | SN A7TV11001-99999, SN ATZD11001-99999 |
| S550 | SN A3NK11001-A3NL99999, SN A3NM11001-99999 |
| S570 | SN A7U711001-799999, SN A7U811001-899999 |
| S590 | SN ANMN11001-99999, SN ANMP11001-99999 |
| S630 | SN A3NT12370-99999, SN A3NU11001-11111, SN A3NU11112-99999 |
| S650 | SN A3NV11001-13098, SN A3NV13099-99999, SN A3NW11001-11248 |
| S750 | SN A3P211001-299999 |
| S770 | SN A39511001-99999, SN A3P411001-99999 |
| T550 | SN A7UJ11001-AJZV12276 |
| T590 | SN ALJU11001-999999, SN B37811001-999999, SN B3Z711001-999999 |
| T630 | SN A7PU11001-11663, SN A7PU11664-99999 |
| T650 | SN A3P012214-099999, SN A3P111242-199999 |
| T750 | SN ANKA11001-A99999 |
| T770 | SN A3P811001-899999, SN A3P911001-999999 |
| T870 | SN A3PG11001-99999, SN A3PH11001-99999 |
Frequently asked questions
What does Bobcat code D7518 mean?
It means the drive controller checked the right swash plate sensor at startup and found its voltage outside the neutral range of 2.08 to 2.92 volts, which caused the engine to shut down.
Why did my Bobcat shut down right after I turned the key?
D7518 is a startup-only check. If the right swash plate sensor is not reading in the neutral band when PTOL is enabled at key-on, the controller sets the code and shuts the engine down immediately, rather than during normal driving.
Can I just clear D7518 and keep running?
The listed clearing step is to cycle power, but that only clears the code. If the underlying cause, such as a bad sensor, loose connector, or off-center pump, is still present, the code is likely to return the next time the machine starts.
Is D7518 an electrical problem or a hydraulic problem?
It can be either. The sensor and wiring side is electrical, covering the sensor itself, connectors, and the SJC harness. But the root cause can also be hydraulic, such as contamination in the hydraulic system or the pump not being physically centered.
What is the swash plate sensor's normal voltage range?
The sensor's full output signal range is 1.0 to 4.0 volts, but the drive controller specifically checks for a neutral reading between 2.08 and 2.92 volts at startup.
Which Bobcat machines can show code D7518?
It applies to Bobcat S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 models, as well as T870.
What if the code only shows up sometimes?
If D7518 is intermittent and not active when you test the machine, the exact cause may not be identifiable right away. Likely culprits still include loose connections, corrosion, pushed-back pins, the controller, or the wire harness, so a careful inspection of all of these is worth doing even without an active fault.