What it means
The auto-shift manual control circuit reports a intermittent 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 sends the driver's shift requests to the control module, which checks that the input remains stable. P0954 sets when that signal cuts in and out, often because of a loose connector, a noisy ground reference, or a contact that opens when vibration moves the harness.
Common causes
Most likely first.
- Connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
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
- Check freeze-frame data and any stored event details, then monitor the manual control input while selecting each request to see whether it drops out.
- Inspect the control connector for incomplete seating, loose pins, corrosion, or movement that could interrupt contact.
- Trace the harness and ground reference for chafing, poor connections, or routing that allows vibration to disturb the circuit.
- With live data displayed, gently move the harness and connector to see whether the input changes unexpectedly.
- If no connection fault is found, test circuit continuity and ground stability against the manufacturer's specification.
Common fixes
- Fully seat and secure the manual control connector.
- Clean or replace terminals with intermittent contact.
- Repair chafed wiring or a noisy ground connection.
- Replace a control switch that loses contact under movement.
Can I keep driving?
Manual shift requests may disappear or return unpredictably, so do not depend on manual mode for precise gear selection. If the intermittent fault coincides with harsh shifts or limp mode, limit driving and have the transmission checked promptly.
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.