What it means
Voltage on the 4WD-Low switch line is below the expected window. Usually a short to ground or a stuck-closed switch.
At a glance
- Usually lights the check-engine light
How it works
The 4WD Low switch circuit carries the signal used to identify whether the transfer case is in low range. The controller monitors the voltage on that signal line. This code sets when the voltage falls below its expected window, commonly because the line is shorted to ground, the switch is stuck closed, or a connector has a poor electrical contact.
Common causes
Most likely first.
- Switch wire shorted to ground
- Switch stuck in closed position
- Connector pins corroded - high contact resistance
Symptoms
- 4WD Low indicator or warning light may be on
- 4WD Low may appear engaged when it is not
- 4WD Low status may display incorrectly
How to diagnose it
- Save freeze-frame data and check scan-tool 4WD Low switch status against the transfer-case position and any related codes.
- Check whether the display says low range is engaged when the transfer case is not in low range.
- Inspect the switch connector and wiring for a short to ground, corrosion, loose terminals, or damaged insulation.
- With live switch data displayed, operate the transfer case and gently move the harness to see whether the low signal remains stuck or changes.
- Test the switch and signal wire for a short to ground or stuck-closed contact, following the manufacturer’s wiring diagram and specification.
Common fixes
- Repair wiring that is shorted to ground.
- Clean or replace corroded connector terminals and restore a secure connection.
- Replace the 4WD Low switch if it remains closed when it should change state.
- Repair damaged switch-circuit insulation or connectors.
Can I keep driving?
Do not trust a low-range indication that appears engaged when the transfer case is not; verify the selected range using the vehicle’s normal procedure and avoid demanding terrain. Incorrect status may lead to unexpected gearing or traction behavior.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.