Bobcat M3706 (37-06) Fault Code: Two Speed Secondary Error Off
Also shown on the panel as 37-06 · Also called Two-Speed Second Output Short to Ground
Two Speed Secondary Error Off · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Bobcat fault code M3706 (panel display 37-06) sets when the gateway controller commands the two speed make-up solenoid but does not detect voltage on signal wire 4360 or return wire 2360. When this code is active, two speed travel is disabled until the fault is fixed and power is cycled.
Medium severity. M3706 does not stop the machine from working, but it disables two speed travel, which limits productivity and can mean unexpected loss of high range mid-task. It should be diagnosed the same shift it appears, especially if the machine is used for travel-heavy work.
What does Bobcat error code M3706 mean?
M3706 is set by the gateway controller when it commands the two speed make-up solenoid on and does not see the expected voltage on signal wire 4360 or return wire 2360. The two speed make-up solenoid's job is to supply charge pressure to the inactive motor pistons whenever the machine is running in high range. This solenoid is only energized in high range, so the fault only shows up under those conditions.
Because the controller cannot confirm the solenoid circuit is working correctly, it disables two speed operation as a protective measure. The machine will still drive and operate normally in low range, but the operator will not be able to shift into or use high range travel until the fault is corrected.
Common causes of M3706
- Signal wire 4360 or return wire 2360 shorted to ground
- Faulty two speed make-up solenoid
- Faulty gateway controller
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, the two speed make-up solenoid connector, or the mainframe harness
- Loose connections, corrosion, pushed-back pins, controller issues, or wire harness problems in combination, especially if the code is intermittent and not present at the time of testing
How to troubleshoot Bobcat M3706: first checks
- Confirm the conditions under which the code sets: key switch or run/enter on, Press To Operate Loader (PTOL) enabled, engine running, and two speed enabled. If any of these are not met, the code will not be active for testing.
- Inspect the two speed make-up solenoid connector and the gateway controller connectors for moisture, corrosion, or pins that have been pushed back out of position.
- Visually and physically trace signal wire 4360 and return wire 2360 for chafing, pinch points, or shorts to ground, particularly anywhere the mainframe harness runs near sharp edges or moving parts.
- Check the two speed make-up solenoid itself for proper function and correct resistance/operation, since a failed solenoid can mimic a wiring short.
- If the code is intermittent, wiggle-test the harness and connectors while watching for the fault to reappear, since intermittent faults often trace back to loose connections or corrosion that isn't visible at rest.
How the code clears
Once the repair is complete, the fix for M3706 is to cycle power on the machine. No separate reset procedure or software step is listed beyond turning the key off and back on.
Affected models and serial ranges
M3706 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-ATZC99999 |
| 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 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, SN A3PH11001-99999 |
Frequently asked questions
What does Bobcat code M3706 mean?
It means the gateway controller commanded the two speed make-up solenoid on, but did not detect voltage on signal wire 4360 or return wire 2360. This solenoid supplies charge pressure to the inactive motor pistons while the machine is in high range.
Will M3706 stop my Bobcat from running?
No, but it disables two speed travel. The machine can still be operated in low range while the fault is present.
What triggers M3706 to set in the first place?
The code can only be active when the key switch or run/enter is on, Press To Operate Loader (PTOL) is enabled, the engine is running, and two speed is enabled. It relates specifically to high range operation since that is the only time the two speed make-up solenoid is energized.
What are the most common causes of this code?
The most common causes are a short to ground on signal wire 4360 or return wire 2360, a failed two speed make-up solenoid, a faulty gateway controller, or moisture and corrosion in the related connectors and harness.
The code comes and goes. Why is it hard to diagnose?
Intermittent M3706 faults are often caused by loose connections, corrosion, or pushed-back pins that only cause a fault under vibration or specific conditions. If the code is not active during testing, the exact cause may not be identifiable at that time.
How do I clear M3706 after repair?
Cycle power on the machine. No other reset procedure is listed for this code.
Which Bobcat models can show code M3706?
This code applies to the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 and T870 models.