Bobcat D7574 (75-74) Fault Code: Right Wheel Speed Uncommanded Motion
Also shown on the panel as 75-74 · Also called Drive Right Wheel Speed Uncommanded Motion
Right Wheel Speed Uncommanded Motion · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
D7574 (panel code 75-74) sets when the Drive/Drive Plus Controller sees pulses from the right speed sensor while the joysticks and swash plates are sitting in neutral. In plain terms, the controller thinks the right side of the machine is moving when it should not be. When this code sets, the engine shuts down.
High severity. D7574 causes an engine shutdown as soon as it sets, which stops work immediately. It is not a catastrophic failure code by itself, but the sudden shutdown while operating can be a real safety issue if it happens on a slope, near an edge, or in traffic. Treat it as a stop-now, diagnose-before-restart situation.
What does Bobcat error code D7574 mean?
D7574 is a Bobcat drive/drive plus controller fault tied to the right-side wheel or track speed sensor. The controller constantly compares joystick and swash plate position against actual wheel speed sensor pulses to figure out whether the machine is moving and how fast. When the joysticks and swash plates are sitting in neutral but the controller still sees speed pulses from the right sensor, it interprets that as uncommanded motion, meaning the machine appears to be moving when it was told to stay still.
On wheeled machines, the sensor lives in the motor carrier and reads magnets on a rotating disk. On track machines, the sensor is in the drive motor and reads the teeth on a metal sprocket. Either way, the logic is the same: pulses with no command input equals a fault.
Because uncommanded motion is a safety-critical condition, Bobcat has the engine shut down automatically whenever D7574 sets. That protects the operator and bystanders but also means the machine is dead in the water until the fault is found and cleared.
Common causes of D7574
- Rub through on the AWS/SJC wire harness, which can cause a wire to short or ground out and send false pulse signals to the controller.
- A failing or misreading right wheel speed sensor.
- A fault in the drive/drive plus controller itself.
- A problem with the hydrostatic pump.
- Moisture, corrosion, or pushed-back pins in the drive/drive plus controller connectors or in the AWS/SJC harness connectors.
- Intermittent causes that may not be reproducible at the time of testing, including loose connections, corrosion, pushed-back pins, the controller, the wire harness, or some combination of these problems.
How to troubleshoot Bobcat D7574: first checks
- Confirm the conditions under which the code set: key switch/run-enter on, PTOL enabled, and engine running are all required for the code to be active.
- Visually inspect the AWS/SJC wire harness routing for chafe points or rub-through, especially anywhere it crosses moving parts or sharp edges.
- Check the right wheel speed sensor and its wiring for damage, looseness, or contamination, and confirm it is reading the disk magnets (wheel machines) or sprocket teeth (track machines) correctly.
- Pull the drive/drive plus controller connectors and the AWS/SJC harness connectors and inspect for moisture, corrosion, or pushed-back pins.
- If the code is not currently active, treat it as intermittent: recheck all connections, terminals, and grounds since the fault may not reproduce on demand.
- If sensor, harness, and connector checks come back clean, consider the drive/drive plus controller or the hydrostatic pump as possible causes.
How the code clears
Once the repair is complete, the only listed step to clear D7574 is to cycle power on the machine. No separate reset procedure or software step is listed beyond cycling power.
Affected models and serial ranges
D7574 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 D7574 mean?
It means the drive/drive plus controller detected speed pulses from the right wheel speed sensor while the joysticks and swash plates were in neutral, which the controller reads as uncommanded motion on the right side of the machine.
Why did my Bobcat shut down when D7574 appeared?
D7574 triggers an automatic engine shutdown as a safety measure any time the controller believes the machine is moving without a drive command.
Is D7574 the same on wheeled and tracked Bobcat machines?
The fault logic is the same, but the sensor setup differs. Wheel machines use a sensor in the motor carrier reading magnets on a rotating disk, while track machines use a sensor in the drive motor reading teeth on a metal sprocket.
What is the AWS/SJC harness mentioned in the causes?
It is the wire harness associated with the drive system's speed sensing and joystick/switch circuits. A rub-through in this harness is listed as one of the possible causes of D7574.
How do I clear D7574 after fixing the problem?
Cycle power on the machine. That is the only clearing step listed for this code.
Can D7574 be intermittent and hard to diagnose?
Yes. If the code is not active at the time of testing, the cause may not be found right away. Likely culprits for intermittent faults include loose connections, corrosion, pushed-back pins, the controller, or the wire harness.
What conditions have to be met for D7574 to set?
The key switch or run/enter switch must be on, PTOL must be enabled, and the engine must be running. Those are the operating conditions required for this code to become active.