Bobcat A8107 (81-07) Fault Code: ACD/RACD Output “B” Open Circuit
Also shown on the panel as 81-07 · Also called ACD Output ‘B’ Open Circuit
ACD/RACD Output “B” Open Circuit · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
A8107 (panel display 81-07) sets when the ACD/RACD controller cannot detect the solenoid wired to output "B" on controller pin J1 B-7 or its return wire on controller pin J1 A-10. When this code is active, output "B" is disabled until the circuit is repaired and power is cycled.
Medium severity. Output "B" is disabled while this code is active, which affects whatever attachment function that output controls. It is not an engine-damage or immediate safety-shutdown code, but the lost function should be diagnosed before relying on that attachment circuit again.
What does Bobcat error code A8107 mean?
A8107 is an open-circuit fault on the ACD/RACD (Attachment Control Device / Remote Attachment Control Device) controller's output "B" circuit. The controller sends current out on pin J1 B-7 to energize a solenoid, then expects a return path back on pin J1 A-10. If the controller cannot detect the solenoid at all, meaning the loop is broken somewhere between those two pins, it logs A8107 and shuts output "B" off as a protective measure.
This code affects whatever attachment function is wired to output "B" on your machine's ACD/RACD system. Since the output is disabled once the fault is detected, you will typically notice a specific attachment function stop working along with the fault code appearing on the display.
The fault is about a broken or interrupted electrical path, not a bad command or software issue. The controller simply can't see the solenoid answering back on the return wire, so it treats the circuit as open.
Common causes of A8107
- Output "B" wiring or return wire open, at controller pin J1 B-7 or controller pin J1 A-10
- Failed or open output "B" solenoid
- Fault inside the ACD/RACD controller itself
- Moisture, corrosion, or pushed-back pins in the ACD/RACD controller connectors, mainframe harness, attachment control harness, or the output "B" solenoid connector
- Intermittent connection issues, including loose connections, corrosion, pushed-back pins, controller faults, or harness problems, or a combination of these, which may not be found if the code is not active during testing
How to troubleshoot Bobcat A8107: first checks
- Verify the key switch is in the run/enter on position, since this is a listed condition for the code to be present
- Inspect the output "B" solenoid connector and the ACD/RACD controller connector (pins J1 B-7 and J1 A-10) for moisture, corrosion, or pins that have been pushed back out of the connector body
- Check the mainframe harness and attachment control harness along the output "B" circuit for chafing, breaks, or loose connections
- Test continuity on the output "B" wire and its return wire between the controller and the solenoid to confirm the circuit is intact end to end
- Check the output "B" solenoid itself for an open coil
- If the code is not currently active, treat it as intermittent and focus inspection on connector corrosion, pushed-back pins, and loose harness connections since these are the most likely intermittent causes
How the code clears
Once the wiring, connector, solenoid, or controller issue is repaired, clear the code by cycling power (turning the key switch off and back on). No separate reset procedure is listed for this code.
Affected models and serial ranges
A8107 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 A8107 mean?
It means the ACD/RACD (Attachment Control Device / Remote Attachment Control Device) controller could not detect the solenoid on output "B", either because the output wire at controller pin J1 B-7 or the return wire at controller pin J1 A-10 is open. The controller disables output "B" when this happens.
What is the panel display form of A8107?
On the Bobcat display, this code appears as 81-07.
Will my attachment stop working with code A8107 active?
Yes. The controller disables output "B" as soon as it detects the open circuit, so whatever function is wired to that output will not operate until the fault is fixed.
How do I clear code A8107 after repairing it?
Cycle power by turning the key switch off and back on. No other reset step is listed.
Which Bobcat machines can show code A8107?
This code applies to Bobcat E35, E42, E45, E55, S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, T770, and T870 models equipped with the ACD/RACD attachment control system.
Why does A8107 come and go instead of staying on?
An intermittent A8107 usually points to a loose connection, corrosion, or a pushed-back pin in the controller connectors, mainframe harness, attachment control harness, or the output "B" solenoid connector. These conditions can make and break contact, so the code may not be present every time you check.
Is A8107 a dangerous code to keep operating with?
It is not listed as an engine or major safety shutdown code, but losing the attachment function tied to output "B" can affect how well you can control that attachment. It should be diagnosed and repaired rather than ignored.