What it means
The auto-shift manual mode circuit reports a low condition. Manual mode shift requests cannot be reliably interpreted.
At a glance
- Usually lights the check-engine light
How it works
The automatic transmission reads manual-mode shift requests through a switch or position sensor circuit. The transmission control module monitors the circuit signal level while the selector is operated. P0957 sets when that signal stays lower than expected, which can happen with a short to ground or a switch held closed.
Common causes
Most likely first.
- Wire shorted to ground
- Switch stuck closed
- Connector pins corroded - high contact resistance
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
- Record freeze-frame data and check live manual-mode input data to see whether the signal remains active or low when no manual shift is requested.
- Move the selector through manual mode and watch whether the upshift and downshift inputs change or remain stuck.
- Inspect the switch or sensor connector and harness for chafing, pinched insulation, corrosion, or a wire touching ground.
- With the circuit isolated as specified by the manufacturer, check for an unintended short to ground and inspect the switch contacts for a stuck-closed condition.
- If the signal is normal at the switch but low at the transmission control module, test the intervening wiring and connector terminals.
Common fixes
- Clean and reseat corroded or loose manual-mode circuit connections.
- Repair wiring shorted to ground.
- Replace a manual-mode switch that remains closed when it should be open.
- Clear the fault and verify that the live input changes only when the selector requests a manual shift.
Can I keep driving?
If the vehicle still shifts normally, drive only as needed and avoid manual mode until the fault is repaired. Stop if shifting becomes harsh, slipping, or unpredictable, because continued operation can increase transmission wear.
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.