P0950: Auto Shift Manual Control Circuit

What it means

The auto-shift manual control circuit reports a fault condition. Manual mode shift requests cannot be reliably interpreted.

At a glance

• Usually lights the check-engine light

How it works

The auto-shift manual control circuit carries the driver's requests to change gears manually while using automatic transmission mode. P0950 sets when the control module detects a fault in that circuit and cannot reliably interpret those requests; a failed switch contact or wiring fault may be responsible.

Common causes

Most likely first.

1. Switch contact failed
2. Wiring fault

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

1. Save freeze-frame data and use live data to see whether manual upshift and downshift requests are recognized when the control is operated.
2. Inspect the manual shift control and its connector for damage, looseness, corrosion, or liquid contamination.
3. Check the circuit wiring and grounds between the control and module for opens, shorts, or poor connections.
4. Operate the control while monitoring its input signal to see whether the signal changes consistently.
5. If the wiring is sound, test the switch contacts against the manufacturer's specification.

Common fixes

• Reconnect or clean a loose or corroded manual control connector.
• Repair damaged wiring or a poor ground in the manual control circuit.
• Replace a manual shift switch with failed contacts.
• Repair a confirmed module input fault.

Can I keep driving?

Automatic shifting may remain available, but manual gear requests may not work reliably. Drive gently and avoid relying on manual mode for passing, steep descents, or other situations where a selected gear matters.