Bobcat D7556 (75-56) Fault Code: Right Reverse Drive Solenoid Error Off
Also shown on the panel as 75-56 · Also called Drive Right Reverse Drive Solenoid Error Off
Right Reverse Drive Solenoid Error Off · ai-assisted, editor-reviewed · Last updated 2026-07-21
TL;DR
D7556 (panel display 75-56) sets when the drive/drive plus controller commands the right reverse drive solenoid but does not detect voltage through it. The machine drops into speed management mode until the fault is resolved, so reverse drive on the right side will feel limited or wrong until this is fixed.
Medium severity. The machine keeps running but drops into speed management mode, which limits performance and signals a real circuit or solenoid fault. It should be diagnosed before continued operation, especially in production work where consistent drive response matters for safety.
What does Bobcat error code D7556 mean?
D7556 is set by the drive or drive plus controller when it commands the right reverse drive solenoid to energize but does not see voltage feedback through that circuit. The controller varies solenoid voltage based on joystick signal input, and when it cannot confirm the solenoid is getting the voltage it expects, it flags the fault.
This is a 'voltage not detected' or open/no-signal type fault on the right reverse drive circuit, not a stuck-high or shorted-to-power fault. When it sets, the loader automatically switches to speed management mode, which is a reduced or controlled operating mode meant to keep the machine usable but limited until repairs are made.
Because this affects right side reverse drive specifically, operators may notice pulling, hesitation, or reduced response when trying to reverse or turn using the right drive circuit.
Common causes of D7556
- Signal wire 4250 or return wire 2650 shorted to ground or open, breaking the feedback path the controller needs to confirm solenoid voltage
- Fault in the right reverse drive solenoid itself, preventing it from drawing or passing the commanded voltage
- Fault in the drive/drive plus controller, either in the output driver for this circuit or in its internal detection logic
- Moisture, corrosion, or pushed-back pins in the drive/drive plus controller connectors, the right reverse drive solenoid connector, or the AWS/SJC wire harness connectors
- Intermittent condition not present at time of testing, which can still trace back to loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these
How to troubleshoot Bobcat D7556: first checks
- Confirm the conditions for the code are present: key switch/run-enter on, PTOL enabled, engine running, and a reverse drive command being given, since the controller only evaluates this fault under those conditions
- Inspect the right reverse drive solenoid connector and the drive/drive plus controller connectors for moisture, corrosion, or pins that have been pushed back out of place
- Check signal wire 4250 and return wire 2650 for continuity and for any short to ground or open circuit condition along their length
- Inspect the AWS/SJC wire harness connectors in this circuit for the same corrosion, moisture, or pushed-back pin issues
- Test the right reverse drive solenoid directly to rule out an internal solenoid fault versus a wiring or controller issue
- If the code is not currently active, treat it as intermittent and focus on loose connections, corrosion, and pushed-back pins first since those are the most common intermittent causes
How the code clears
Cycle power to the machine once the repair is complete. No separate clearing step is listed beyond a power cycle.
Affected models and serial ranges
D7556 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 D7556 mean on a Bobcat loader?
It means the drive or drive plus controller commanded the right reverse drive solenoid to energize but did not detect the expected voltage through that circuit. The machine responds by switching into speed management mode until the issue is corrected.
Is it safe to keep working with D7556 active?
The machine will still run in speed management mode, but this is a limited operating mode, not normal performance. It is best to diagnose the fault as soon as practical rather than continue working with reduced or unpredictable reverse drive response on the right side.
What is speed management mode?
It is the reduced or controlled operating mode the loader enters automatically when this solenoid feedback fault is detected. It is meant to keep the machine operable but limited until the underlying wiring, solenoid, or controller issue is fixed.
Which wires are involved in D7556?
Signal wire 4250 and return wire 2650 are the two wires specifically named for this circuit. A short to ground or an open in either wire can set this code.
How do I clear D7556 after repair?
Cycle power to the machine after completing the repair. No additional reset or relearn procedure is listed for this code.
What if the code is intermittent and I can't find the fault?
Intermittent D7556 codes that are not active at the time of testing are usually caused by loose connections, corrosion, pushed-back pins, the controller, or the wire harness, sometimes in combination. Focus your inspection on connector condition first since that is the most common intermittent cause.
How is D7556 different from D7555, the Right Forward Drive Solenoid Error?
D7556 covers the right reverse drive solenoid circuit while D7555 covers the right forward drive solenoid circuit on the same side. Both are voltage-not-detected faults, so a machine that struggles specifically going backward on the right side points to D7556, while forward-side trouble points to D7555. If you are chasing forward drive symptoms instead of reverse, check the D7555 page.