Bobcat M1606 (16-06) Fault Code: Traction Lock Hold Solenoid Short to Ground
Also shown on the panel as 16-06
Traction Lock Hold Solenoid Short to Ground · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M1606 (panel code 16-06) sets when the gateway controller commands the traction lock hold solenoid on wire 4200 but does not see voltage return, usually because that circuit is shorted to ground. When this code is active, the machine disables traction, so you will lose drive function until it is fixed.
High severity. Traction is disabled the moment this code is active, so the machine cannot be driven safely or at all. It is not a code to run through, but it is an electrical fault rather than an immediate engine or structural damage risk.
What does Bobcat error code M1606 mean?
M1606 is set by the gateway controller when it commands the traction lock hold solenoid, which runs on wire 4200, and does not detect voltage on that circuit as it should. This solenoid is energized whenever traction is enabled, right after a traction pull command is given.
In plain terms, the controller tries to turn on the solenoid that holds traction engaged, and the feedback it gets back tells it the wire is grounded out instead of carrying the expected voltage. Because the controller cannot verify the solenoid circuit is working correctly, it shuts traction down as a protective measure.
This means once M1606 is active, you will not be able to drive the machine until the fault is cleared and traction is re-enabled through a power cycle.
Common causes of M1606
- Controller output wire 4200 shorted to ground
- Faulty traction lock solenoid
- Faulty gateway controller
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, the traction lock solenoid connector, or the mainframe harness
- Intermittent wiring or connection issues (loose connections, corrosion, pushed-back pins, the controller, or the wire harness, alone or in combination) if the code is not active at the time of testing
How to troubleshoot Bobcat M1606: first checks
- Confirm the conditions for the code are present: key switch in run/enter, Press To Operate Loader (PTOL) enabled, and engine running
- Inspect the gateway controller connectors and the traction lock solenoid connector for moisture, corrosion, or pushed-back pins
- Trace wire 4200 from the gateway controller to the traction lock solenoid and check for a short to ground along its length and at the mainframe harness
- Test the traction lock hold solenoid itself for an internal short to ground
- If the code is not currently active, treat it as intermittent and closely inspect connections, pins, and harness routing since the root cause may not show up during static testing
- Consider the gateway controller as a possible cause if the wiring and solenoid check out clean
How the code clears
Once the repair is complete, clear M1606 by cycling power on the machine. No separate reset procedure beyond a power cycle is listed for this code.
Affected models and serial ranges
M1606 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 M1606 mean?
It means the gateway controller commanded the traction lock hold solenoid on wire 4200 to turn on but detected the circuit shorted to ground instead of seeing the expected voltage. As a result, the machine disables traction.
Can I still drive my Bobcat with M1606 active?
No. When M1606 is active, traction is disabled by the controller as a protective response, so the machine will not drive until the fault is fixed and power is cycled.
What is wire 4200 on a Bobcat loader?
Wire 4200 is the controller output that energizes the traction lock hold solenoid whenever traction is enabled following a traction pull command.
What usually causes M1606?
The most common causes are wire 4200 shorted to ground, a failed traction lock solenoid, moisture or corrosion in the gateway controller or solenoid connectors, pushed-back pins, or a faulty gateway controller itself.
How do I clear M1606 after repairs?
Cycle power on the machine. That is the only clearing step listed for this code.
Why does M1606 come and go instead of staying on?
Intermittent M1606 codes are usually tied to loose connections, corrosion, or pushed-back pins that only cause a short under certain vibration, temperature, or connector movement conditions. If the code isn't active during testing, a careful inspection of connectors and harness routing is needed to find the intermittent fault.
Which Bobcat models can show code M1606?
M1606 applies across the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 model lines, and the T870.