C0071: 2/4 Wheel Drive Status Input (Subfault)

What it means

This code identifies a fault associated with the 2/4 wheel drive status input. The specific failure depends on the diagnostic subtype.

At a glance

• Usually lights the ABS or stability-control warning light

How it works

The 2/4-wheel-drive status input tells the ABS or stability system which drivetrain mode the vehicle is using, so it can account for the different wheel and traction behaviour. This subfault code points to that status input; its diagnostic subtype helps determine whether the switch signal, wiring, or reported state is at fault.

Common causes

Most likely first.

1. Switch or wiring fault

Symptoms

• ABS or stability-control warning light
• Stability control may be limited or disabled

How to diagnose it

1. Read the module's subtype, companion codes, and freeze-frame data to identify the status input condition that triggered the code.
2. Check the live 2/4-wheel-drive status value while operating the selector through its available positions as directed by the owner's or manufacturer's procedure.
3. Inspect the drivetrain-mode switch, its connector, and the wiring toward the control module for damage, corrosion, or loose terminals.
4. Check the switch signal and circuit continuity against the manufacturer's wiring information and specifications.
5. If the input circuit tests correctly, check the relevant module communication and input interpretation using the manufacturer's diagnostic procedure.

Common fixes

• Secure or clean the drivetrain-mode switch connector.
• Repair damaged wiring or poor terminals in the 2/4-wheel-drive status circuit.
• Replace a confirmed faulty mode switch.
• Address a module or communication fault only after the input and wiring have passed testing.

Can I keep driving?

ABS or stability assistance may be limited if the system cannot determine the selected drivetrain mode. Drive cautiously, especially on low-traction surfaces, and confirm the vehicle is in the intended drive mode before continuing.