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 2026-07-13
TL;DR
Bobcat code 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 fixed and power is cycled.
Medium severity. The machine keeps running but is limited to speed management mode, which reduces normal drive performance. It is not an immediate safety shutdown, but reverse drive control on the right side is compromised, so get it diagnosed before continuing regular operation.
What does Bobcat error code D7556 mean?
D7556 is a Bobcat drive system fault tied to the right reverse drive solenoid circuit. The drive/drive plus controller varies voltage to the drive solenoids based on joystick signal input, and this code fires when it expects to see voltage at the right reverse solenoid but does not detect it.
When this happens, the loader automatically shifts into speed management mode as a protective response. This is the controller's way of limiting drive performance until the underlying electrical or mechanical issue with the right reverse circuit is resolved.
This code affects a wide range of Bobcat skid-steer and track loader models, including the S510 through S770 and T550 through T870 lines, since they share the same drive/drive plus controller logic.
Common causes of D7556
- Signal wire 4250 or return wire 2650 shorted to ground or open
- Failed right reverse drive solenoid
- Faulty drive/drive plus controller
- Moisture, corrosion, or pushed-back pins in the drive/drive plus controller connectors, right reverse drive solenoid connector, or AWS/SJC wire harness
- Intermittent condition from loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these problems that may not be present at the time of testing
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
- Inspect the right reverse drive solenoid connector and the drive/drive plus controller connectors for moisture, corrosion, or pushed-back pins
- Check the AWS/SJC wire harness along its full run for chafing, loose connections, or damage
- Test signal wire 4250 and return wire 2650 for a short to ground or an open circuit
- Inspect the right reverse drive solenoid itself for proper operation and resistance
- If the code is not currently active, treat it as intermittent and recheck all connectors, harness routing, and terminals for loose or corroded pins before assuming the controller is bad
How the code clears
Once the repair is complete, cycle the key power off and back on. No separate clearing step is listed beyond cycling power.
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 Bobcat code D7556 mean?
It means the drive/drive plus controller commanded the right reverse drive solenoid but did not detect voltage coming through it, so the loader drops into speed management mode until the issue is fixed.
Can I keep operating my Bobcat with code D7556 active?
The machine will still run, but it operates in speed management mode with reduced drive performance. It's best to stop and diagnose the issue rather than keep working with reduced control over reverse drive.
What wires are involved in D7556?
Signal wire 4250 and return wire 2650 are the two wires tied to the right reverse drive solenoid circuit. Either one being shorted to ground or open can trigger this code.
How do I clear D7556 after I fix it?
Cycle the key power off and back on. That is the only clearing step listed for this code.
Why does D7556 come and go instead of staying on?
Intermittent behavior usually points to loose connections, corrosion, or pushed-back pins in the connectors rather than a fully failed solenoid or controller. If the code isn't active when you test, recheck all connections carefully since the root cause may not show up right away.
Which Bobcat models can get code D7556?
This code applies to S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, T770, and T870 models.
What is speed management mode on a Bobcat loader?
It's a reduced-performance operating mode the drive/drive plus controller switches to when it detects a fault like D7556, limiting drive output until the fault is resolved and power is cycled.