Bobcat A8507 (85-07) Fault Code: ACD/RACD Output “F” Open Circuit
Also shown on the panel as 85-07 · Also called ACD Output ‘F’ Open Circuit
ACD/RACD Output “F” Open Circuit · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
A8507 (panel form 85-07) sets when the ACD/RACD controller cannot detect the solenoid wired to output "F", controller pin J1 B-19, or its return wire on controller pin J1 A-18. When it sets, output "F" is disabled until the circuit is repaired and power is cycled.
Medium severity. Output "F" is disabled while this code is active, which means whatever attachment function runs on that output will not work. This is not an engine or hydraulic system shutdown, but it does take away a function until fixed, so it should be diagnosed before relying on that attachment feature.
What does Bobcat error code A8507 mean?
A8507 is set by the ACD/RACD controller, which manages Bobcat's Advanced Control of Discharge or Reverse Advanced Control of Discharge attachment interface. Output "F" is one of the controller's solenoid driver circuits, wired out through controller pin J1 B-19 with its return path on controller pin J1 A-18.
This code means the controller sent a signal out on output "F" but never saw the solenoid respond, meaning the circuit is effectively open. It could be a break in the output wire, a break in the return wire, a bad solenoid, or a fault inside the controller itself. Once the controller detects this open circuit, it shuts down output "F" entirely so that function stops operating until the issue is resolved.
This affects a wide range of Bobcat skid-steer, track loader, and excavator models, including the E35, E42, E45, E55, S510 through S650, S750, S770, T550 through T650, T750, T770, and T870.
Common causes of A8507
- Output "F" wire (controller pin J1 B-19) or its return wire (controller pin J1 A-18) is open, meaning broken, disconnected, or cut somewhere in the harness.
- The output "F" solenoid itself has failed internally (open coil).
- The ACD/RACD controller has an internal fault.
- Moisture, corrosion, or pushed-back pins in the ACD/RACD controller connectors, mainframe harness, attachment control harness, or the output "F" solenoid connector.
- Intermittent condition: if the code is not active at the time of testing, the exact cause may not be identifiable immediately. Likely culprits in these cases are loose connections, corrosion, pushed-back pins, the controller, the wire harness, or some combination of these.
How to troubleshoot Bobcat A8507: first checks
- Confirm the key switch is on (run/enter position), since this is the condition required for the controller to check output "F" and set the code.
- Inspect the ACD/RACD controller connectors, the mainframe harness, and the attachment control harness for moisture, corrosion, or pins that have been pushed back out of their sockets.
- Check the wiring at controller pin J1 B-19 (output "F") and pin J1 A-18 (return) for continuity, looking for an open circuit anywhere along that path.
- Inspect the output "F" solenoid connector and the solenoid coil itself for an open winding or damaged wiring.
- If the code is not currently active, treat it as possibly intermittent and check for loose connections and corrosion at every connector along the output "F" circuit, since the fault may not reproduce on demand.
How the code clears
Once the wiring, solenoid, or controller issue is repaired, cycle the key power (turn the machine off and back on) to clear the code. No separate clearing procedure beyond a power cycle is listed for this code.
Affected models and serial ranges
A8507 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 A8507 mean?
It means the ACD/RACD controller could not detect the solenoid on output "F," either because the output wire (pin J1 B-19), the return wire (pin J1 A-18), the solenoid, or the controller has an open circuit or fault. The controller disables output "F" when this happens.
What is the panel display form of A8507?
On the machine's display panel, this code appears in the numeric form 85-07.
Will my attachment stop working if I get A8507?
The specific function tied to output "F" will be disabled until the fault is fixed. Other machine functions are not described as affected by this code.
How do I clear A8507 after I fix it?
Cycle the key power, meaning turn the machine off and back on, once the repair is complete. No other clearing steps are listed.
Why does A8507 come and go instead of staying on?
If the code is intermittent, the open circuit may only occur under certain conditions, such as vibration or temperature changes affecting a marginal connection. Likely causes in intermittent cases include loose connections, corrosion, pushed-back pins, a wire harness issue, or a controller problem.
Which Bobcat models can show code A8507?
This code applies to the E35, E42, E45, E55, S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, T770, and T870.
Is A8507 caused by the solenoid or the wiring?
It can be either. The controller cannot tell the difference between an open output wire, an open return wire, a failed solenoid coil, or an internal controller fault from the code alone, so all of these need to be checked.