Bobcat M3705 (37-05) Fault Code: Two Speed Secondary Error On
Also shown on the panel as 37-05 · Also called Two-Speed Second Output Short to Battery
Two Speed Secondary Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M3705 (panel code 37-05) sets when the gateway controller sees voltage on the two speed make-up solenoid signal wire 4360 when it has not commanded that solenoid on. When this code is active, two speed drive is disabled until the fault is fixed and power is cycled.
Medium severity. Two speed is disabled as a protective measure but the machine can still be driven in low range. This is a drivability fault, not an immediate safety or engine-damage emergency, so it should be diagnosed the same shift but does not require shutting the machine down on the spot.
What does Bobcat error code M3705 mean?
M3705 is set by the gateway controller when it detects voltage present on signal wire 4360, the wire that controls the two speed make-up solenoid, at a time when the controller has not commanded that solenoid to be on.
The two speed make-up solenoid supplies charge pressure to the inactive motor pistons whenever the machine is running in two speed high range. It is only supposed to be energized in high range. If the controller sees voltage on this circuit when it should be off, it assumes a wiring or solenoid fault and disables two speed entirely to protect the drive system.
In practical terms, this means the operator will lose access to high range travel speed until the wiring or solenoid problem is found and corrected.
Common causes of M3705
- Signal wire 4360 shorted to battery voltage
- Return wire 2360 shorted to supply voltage, or shorted to signal wire 4360
- 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
- Intermittent fault: if the code is not active at the time of testing, the cause may involve a combination of loose connections, corrosion, pushed-back pins, the controller, or the wire harness
How to troubleshoot Bobcat M3705: first checks
- Turn the key switch to run/enter (this is the condition under which the code sets) and check for the active fault before disturbing wiring.
- Visually inspect the two speed make-up solenoid connector, the gateway controller connectors, and the mainframe harness connectors for moisture, corrosion, or pushed-back pins.
- Check signal wire 4360 for a short to battery voltage using a meter with the harness disconnected from the solenoid and controller.
- Check return wire 2360 for a short to supply voltage or for a short to signal wire 4360.
- Test the two speed make-up solenoid itself for correct operation, since a shorted solenoid coil can put voltage back onto the signal wire.
- If the code is intermittent and not present during testing, recheck all connectors and wiring for loose connections and pushed-back pins, since the fault may not be reproducible immediately.
How the code clears
Once the wiring, connector, solenoid, or controller issue is repaired, the fix is to cycle power (turn the key off and back on) to clear the code. No separate reset procedure is listed for this code.
Affected models and serial ranges
M3705 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 M3705 mean?
It means the gateway controller detected voltage on signal wire 4360, which controls the two speed make-up solenoid, when the controller had not commanded that solenoid on. This points to a short to battery voltage somewhere in that circuit.
Will my Bobcat still drive with M3705 active?
Yes, but two speed high range will be disabled. The machine can still operate in low range until the fault is repaired.
What is the two speed make-up solenoid for?
It supplies charge pressure to the inactive motor pistons while the machine is running in two speed high range. It is only energized in high range, never in low range.
How do I clear code M3705 after fixing it?
Cycle power on the machine, meaning turn the key off and back on, after the underlying wiring, connector, or solenoid problem has been corrected. No other reset step is listed.
Which Bobcat models can show M3705?
This code applies to the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 model range.
Why does M3705 come back intermittently?
If the code is not active when tested, the cause can be hard to pin down. Likely culprits are loose connections, corrosion, or pushed-back pins in connectors, or a wiring or controller issue that only shows up under certain conditions.
What wires should a technician check first for M3705?
Start with signal wire 4360 (checking for a short to battery voltage) and return wire 2360 (checking for a short to supply voltage or a short to wire 4360), along with inspecting all related connectors for corrosion or damage.