Bobcat A8602 (86-02) Fault Code: ACD/RACD Output "G" Error On
Also shown on the panel as 86-02 · Also called ACD Output ‘G’ Error On
ACD/RACD Output "G" Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
A8602 (panel display 86-02) sets when the ACD/RACD controller sees voltage on output "G" wire 5400 even though it never sent voltage to energize the attachment solenoid on that circuit. The controller shuts off the output, the attachment on output "G" stops working, and the ACD/RACD icon on the right instrument panel blinks.
Medium severity. The attachment run on output "G" is disabled until the fault is fixed, which can stop attachment-dependent work, but it is not itself a safety-critical drive or lift failure. Treat it as a diagnose-this-shift issue rather than an emergency shutdown.
What does Bobcat error code A8602 mean?
A8602 is set by the ACD/RACD controller (Attachment Control Device / Remote Attachment Control Device) when it detects voltage present on output "G" wire 5400 while it has not commanded that output on. In other words, the controller is seeing power where there shouldn't be any, which points to a short to a power source somewhere in that circuit.
When this happens, the controller protects itself and the attachment by shutting off the electric output entirely. Any attachment wired to output "G" will not function until the fault clears. The right instrument panel shows a blinking ACD/RACD icon so the operator knows the attachment output is disabled.
This code affects the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 skid-steer and compact track loader models, plus the T870.
Common causes of A8602
- Circuit output "G" wire 5400 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.
- Intermittent causes that may not be present at the time of testing, including loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these problems.
How to troubleshoot Bobcat A8602: first checks
- Confirm the key switch is in the run/enter (on) position, since that is the condition required for the controller to set this code.
- Inspect the attachment control harness and mainframe harness connectors for moisture, corrosion, or pins that have been pushed back out of their connector body.
- Check wire 5400 on output "G" for signs of chafing, pinching, or contact with a power source that could cause a short.
- Wiggle-test connectors and harness sections while watching for the fault to change state, since an intermittent fault may not show up during a static check.
- If the wiring and connectors check out, suspect the ACD/RACD controller itself as a possible cause.
How the code clears
Cycle power to clear the code once the repair is complete. No separate clearing step is listed beyond cycling the key switch off and back on.
Affected models and serial ranges
A8602 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 A8602 mean?
It means the ACD/RACD controller found voltage on output "G" wire 5400 without having sent voltage itself, so it suspects a short to a power source and shuts the output off to protect the circuit.
Why did my attachment stop working after this code appeared?
Because A8602 shuts off the electric output on the "G" circuit when it's active, any attachment wired to that output will not run until the fault is found and cleared.
What is the ACD/RACD icon blinking on my Bobcat's instrument panel?
The blinking icon on the right instrument panel is the machine telling you the ACD/RACD controller has an active output error, in this case A8602 on output "G."
How do I clear A8602 after I fix the wiring?
Cycle power to the machine, that is, turn the key off and back on. No other clearing procedure is listed for this code.
What if the code doesn't show up when I test the machine?
That points to an intermittent fault. Possible causes include loose connections, corrosion, pushed-back pins, the controller, or the wire harness, and any combination of these, so a thorough inspection of connectors and harness routing is worth doing even without an active fault.
Which Bobcat models can show code A8602?
It applies to the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, T770, and T870.
Is A8602 a controller problem or a wiring problem?
It can be either. The listed causes include a short to a power source in wire 5400, moisture or corrosion or pushed-back pins in the harness connectors, or a fault in the ACD/RACD controller itself, so both wiring and the controller need to be checked.