Bobcat A8502 (85-02) Fault Code: ACD/RACD Output "F" Error On
Also shown on the panel as 85-02 · Also called ACD Output ‘F’ Error On
ACD/RACD Output "F" Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
A8502 (panel form 85-02) sets when the ACD/RACD controller sees voltage on output "F" wire 5350 without having sent power to energize the attachment solenoid coil. The controller shuts off that electric output, the attachment on output "F" stops working, and the ACD/RACD icon on the right instrument panel blinks.
Medium severity. The affected attachment output is disabled until the fault is cleared, which stops that specific attachment function, but it does not by itself indicate a safety-critical failure of the machine's core systems. Diagnose before relying on the attachment again.
What does Bobcat error code A8502 mean?
A8502 is an electrical fault in the Attachment Control Device / Remote Attachment Control Device (ACD/RACD) system on Bobcat loaders. This system lets the operator control powered attachments from the cab. Output "F" is one of the controller's switched outputs that sends voltage down wire 5350 to energize an attachment solenoid coil.
The controller expects that when it has not commanded output "F" on, there should be no voltage present on that wire. When it detects voltage there anyway, it assumes something outside the controller is feeding power into the circuit that shouldn't be there. To protect the circuit and the controller, it shuts off the output entirely, so the attachment function wired to output "F" will not operate until the fault is fixed and cleared.
The blinking ACD/RACD icon on the right instrument panel is the operator's cue that this code is active and that attachment output is disabled.
Common causes of A8502
- Circuit output "F" wire 5350 to the attachment solenoid is shorted to a power source.
- A fault in the ACD/RACD controller itself.
- Moisture, corrosion, or pushed-back pins in the mainframe or attachment control harness connectors.
- Loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these problems, especially if the code is intermittent and not active at the time of testing.
How to troubleshoot Bobcat A8502: first checks
- Confirm the key switch is in the run/enter position, since that is the condition under which the code is set and can be checked.
- Inspect the attachment control harness and mainframe connectors related to output "F" wire 5350 for moisture, corrosion, or pins that have been pushed back out of their sockets.
- Check wire 5350 for signs of chafing or contact with a power source that could be shorting it, since a short to power on this wire is a listed cause.
- Wiggle-test connectors in the harness while watching for the code to go active, since an intermittent fault may not be present at the time of testing.
- If the wiring and connectors check out, consider the ACD/RACD controller itself as a possible cause, since it's listed as a direct possible cause of this code.
How the code clears
Cycle the key power (turn the key switch off, then back to run/enter) after the repair is complete. No separate clearing step is listed beyond cycling power.
Affected models and serial ranges
A8502 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 ATZC11001-99999 |
| 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 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 A8502 mean?
It means the ACD/RACD controller detected voltage on output "F" wire 5350 without having commanded that output on to energize the attachment solenoid coil. The controller shuts the output off and the attachment on that circuit stops working until the issue is fixed.
Why is my attachment not responding after this code appeared?
Once A8502 is active, the ACD/RACD electric output for "F" is shut off by the controller as a protective measure. The attachment wired to that output will not function again until the fault is diagnosed, repaired, and the code cleared.
What usually causes A8502?
The most common causes are a short to a power source on wire 5350, moisture or corrosion in the mainframe or attachment control harness connectors, pushed-back pins in those connectors, or a failure in the ACD/RACD controller itself.
The code isn't showing right now, does that mean it's fixed?
Not necessarily. If the code is intermittent, it may not be active at the time of testing, and the underlying cause, such as a loose connection, corrosion, or a pushed-back pin, can still be present. Wiggle-testing the harness and connectors can help find intermittent faults.
How do I clear code A8502 after repair?
Cycle the key power, off and then back to run/enter. No separate clearing procedure is listed beyond cycling power.
Which Bobcat machines can show code A8502?
It's listed for the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770, and T870 skid-steer and compact track loader models.
Is A8502 the same as fault 85-02 on the panel display?
Yes. A8502 is the numeric panel form 85-02 displayed with a blinking ACD/RACD icon on the right instrument panel.