What it means
4WD switch input reads stuck low — short to ground or stuck-closed contact. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The 4WD selector switch sends the driver's requested transfer-case mode to the control system. This code sets when the switch input is lower than expected, which can result from a signal wire shorted to ground or a switch contact stuck closed.
Common causes
Most likely first.
- Switch wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Capture freeze-frame data and watch the scan-tool 4WD switch input while selecting each available mode.
- Inspect the selector switch connector and harness for chafing, exposed wire, water intrusion, corrosion, or backed-out pins.
- Move the harness gently while monitoring the input to see whether it changes, and note whether the reading remains low in every selector position.
- With the circuit isolated as directed by the manufacturer, test the signal wire for a short to ground and check connector continuity.
- If the wiring is intact, test the selector switch and then the transfer-case control circuit according to the manufacturer's procedure.
Common fixes
- Repair a signal wire chafed through to ground.
- Clean and secure the selector connector, repairing corroded or damaged terminals.
- Replace a selector switch with a confirmed stuck-closed contact.
- Repair a confirmed transfer-case control circuit fault.
Can I keep driving?
Avoid relying on 4WD until the selector and engaged mode can be verified; choose routes that do not require four-wheel drive. The transfer case may ignore or misread the requested mode.
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.