Bobcat D7544 (75-44) Fault Code: Left Reverse Drive Solenoid Error On
Also shown on the panel as 75-44 · Also called Drive Left Reverse Drive Solenoid Error On
Left Reverse Drive Solenoid Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
D7544 (panel form 75-44) sets when the drive/drive plus controller detects voltage on the left reverse drive solenoid circuit when it did not command that voltage. When this code is active, drive functions are disabled until the fault is cleared and power is cycled.
High severity. Drive functions are disabled whenever this code is active, which stops the machine from being driven. It should be treated as a stop-and-diagnose issue rather than something to run through a shift, since you have no left reverse drive until it's resolved.
What does Bobcat error code D7544 mean?
D7544 is a Bobcat drive system fault that occurs when the drive or drive plus controller sees voltage present on the left reverse drive solenoid circuit at a time when the controller itself did not command that solenoid to be energized. The controller manages drive direction and speed by varying voltage to the drive solenoids based on joystick input, so an unexpected voltage reading on this circuit tells the controller something is wrong upstream, whether that's a wiring short, a bad solenoid, or an internal controller issue.
Because the controller can't trust the state of that circuit, it disables drive functions entirely as a protective measure. This is a safety-oriented response: an unintended or unpredictable drive solenoid state could cause unexpected machine movement, so the controller shuts things down rather than risk it.
Bobcat notes that additional codes D7553, D7554, D7555, or D7556 may also appear alongside D7544. These are related drive circuit codes and, if present, should be diagnosed together rather than treated as separate unrelated problems.
Common causes of D7544
- Signal wire 4280 or return wire 2680 shorted to supply voltage
- A faulty left reverse drive solenoid
- A fault in the drive/drive plus controller itself
- Moisture, corrosion, or pushed-back pins in the drive/drive plus controller connectors or in the AWS/SJC wire harness connectors
- Intermittent faults: if the code isn't active at the time of testing, the root cause may not be found immediately. Probable causes for intermittent codes include loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these
How to troubleshoot Bobcat D7544: first checks
- With the key switch in the run/enter position and the code active, check signal wire 4280 and return wire 2680 for a short to supply voltage using a multimeter and the appropriate wiring diagram
- Inspect the drive/drive plus controller connectors and the AWS/SJC wire harness connectors for moisture, corrosion, or pins that have been pushed back out of place
- Visually and electrically inspect the left reverse drive solenoid itself for damage, corrosion, or an open/shorted coil
- Check for loose or degraded connections anywhere along the harness between the controller and the left reverse drive solenoid
- If the code is not currently active (intermittent), wiggle-test the harness and connectors near the controller and solenoid while watching for the code to reappear, since an intermittent fault may not show up on a static test
How the code clears
Bobcat lists the clearing condition for this code as cycle power. After completing repairs, turn the key switch off and back on to clear the fault. No separate reset procedure beyond cycling power is listed for this code.
Affected models and serial ranges
D7544 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 D7544 mean?
It means the drive or drive plus controller detected voltage on the left reverse drive solenoid circuit when it had not commanded that solenoid on. The controller then disables drive functions until the issue is fixed and power is cycled.
Why does my Bobcat lose drive function when D7544 is active?
The controller disables all drive functions as a protective response any time it can't confirm the actual state of the left reverse drive solenoid circuit matches what it commanded. This prevents unpredictable or unintended machine movement.
What is the numeric panel code for D7544?
The numeric panel form of D7544 is 75-44.
Are other codes related to D7544?
Yes. Bobcat notes that codes D7553, D7554, D7555, or D7556 may also be generated alongside D7544. If any of these appear together, they should be diagnosed as part of the same drive circuit issue.
How do I clear D7544 after repair?
Cycle power (turn the key switch off, then back on) after completing repairs. No separate reset procedure is listed for this code.
Which Bobcat machines can show code D7544?
This code applies to Bobcat S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 models, based on the affected model list for this code.
What if the D7544 code isn't active when I test the machine?
If the code is intermittent and not present at the time of testing, the root cause may not be identifiable right away. Likely contributors include loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these, so a thorough wiggle-test and connector inspection is worthwhile even without an active fault.