Bobcat A8106 (81-06) Fault Code: ACD/RACD Output “B” Short to Ground
Also shown on the panel as 81-06 · Also called ACD Output ‘B’ Short to Ground, ACD/RACD Output “B” Short to Ground
ACD/RACD Output “B” Short to Ground · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Bobcat fault code A8106 (panel display 81-06) sets when the ACD/RACD controller commands output "B" but does not detect voltage on output "B" (controller pin J1 B-7) or its return wire (controller pin J1 A-10). When this code is active, output "B" is disabled until the fault is resolved and power is cycled.
Medium severity. Output "B" is disabled while the code is active, which will stop whatever attachment function or ACD/RACD circuit that output controls. It is not an engine or hydraulic system-damage code by itself, but losing control of an attachment function can be a real operational and safety issue depending on what is connected, so it should be diagnosed before returning the machine to normal work.
What does Bobcat error code A8106 mean?
A8106 is an electrical fault tied to the ACD (Attachment Control Device) or RACD (Remote Attachment Control Device) system on Bobcat skid steers, compact track loaders, and excavators. The ACD/RACD controller sends commands to solenoid outputs that operate attachment functions. Output "B" is one of these commanded outputs.
This code sets when the controller commands output "B" on but does not see the expected voltage at controller pin J1 B-7, or on the return wire at controller pin J1 A-10. In practice this usually means the circuit is shorted to ground somewhere between the controller and the output B solenoid, so the controller cannot verify the output is working correctly.
As a protective measure, the controller disables output "B" entirely once the code sets. Whatever attachment function that output drives will not work until the fault is found, repaired, and the code is cleared.
Common causes of A8106
- Output "B" wire (controller pin J1 B-7) or its return wire (controller pin J1 A-10) shorted to ground
- Faulty output "B" solenoid
- Faulty ACD/RACD controller
- Moisture, corrosion, or pushed-back pins in the ACD/RACD controller connectors, mainframe harness, attachment control harness, or output "B" solenoid connector
- Intermittent fault: loose connections, corrosion, pushed-back pins, the controller, or the wire harness, alone or in combination, if the code is not active at the time of testing
How to troubleshoot Bobcat A8106: first checks
- Confirm the key switch is in the run/enter on position, since this is the condition required for the code to be active and testable
- Inspect the ACD/RACD controller connectors, mainframe harness connectors, and attachment control harness connectors for moisture, corrosion, or pins that have been pushed back out of their sockets
- Check the output "B" solenoid and its connector for damage, corrosion, or a shorted winding
- Test output "B" (controller pin J1 B-7) and the return wire (controller pin J1 A-10) for a short to ground using a multimeter with the harness disconnected from the controller
- If the code is not currently active, wiggle-test the harness and connectors at the controller, mainframe, and attachment harness while watching for the code to reappear, since the fault may be intermittent
How the code clears
Once the shorted wiring, solenoid, controller, or connector issue is repaired, cycle the key switch power off and back on. No separate clearing step is listed beyond cycling power.
Affected models and serial ranges
A8106 appears in our records across 20 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| E35 | SN A93K110001-99999, SN AC2P11001-99999 |
| E42 | SN AG3411001-99999 |
| E45 | SN AG3G11001-99999, SN AHHC11001-99999 |
| E55 | SN ARWM11001-99999, SN ASW311001-99999 |
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-99999 |
| 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 A3NT10001-12369, SN A3NT12370-99999, SN A3NU11001-11111, SN A3NU11112-99999 |
| S650 | SN A3NV11001-13098, SN A3NV13099-99999, SN A3NW11001-11248, SN A3NW11249-99999 |
| 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 |
Frequently asked questions
What does Bobcat code A8106 mean?
It means the ACD/RACD controller commanded output "B" on but did not detect the expected voltage on output "B" (pin J1 B-7) or its return wire (pin J1 A-10). This points to a short to ground somewhere in that circuit.
Will my attachment still work with code A8106 active?
No. Once A8106 sets, the controller disables output "B" entirely, so whatever attachment function relies on that output will not operate until the fault is fixed.
What is the panel display number for A8106?
On the display panel, A8106 appears in numeric form as 81-06.
How do I clear code A8106 after repairs?
Cycle the key switch power off and back on. That is the only clearing step listed for this code.
Which Bobcat machines can show code A8106?
This code applies to Bobcat E35, E42, E45, E55 excavators, S510, S530, S550, S570, S590, S630, S650, S750, S770 skid steers, and T550, T590, T630, T650, T750, T770, T870 compact track loaders.
What if the A8106 code isn't active when I test the machine?
If the fault is intermittent and not present during testing, the cause may not be identifiable right away. Likely culprits still include loose connections, corrosion, pushed-back pins, the controller itself, or the wire harness, possibly more than one at once.
Could the ACD/RACD controller itself be the problem instead of the wiring?
Yes. The controller is listed as one of the possible causes of A8106, along with the output "B" solenoid and the wiring, so if wiring and the solenoid check out, the controller should be evaluated.