Auto Shift Manual Mode Circuit Low
Diagnostic trouble code P0957 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected a low voltage condition in the auto shift manual mode circuit. This circuit is responsible for managing the manual shifting feature (often called Tiptronic, Autostick, or Sport mode) of an automatic transmission, and a low voltage signal usually points to a short to ground or a faulty switch.
While this code typically will not leave you stranded, it disables the manual shifting feature of the automatic transmission. It should be diagnosed soon to restore full transmission functionality and ensure no underlying wiring issues cause further electrical problems.
Common symptoms
- Illuminated Check Engine Light
- Inability to use the manual shift mode (paddle shifters or gear selector)
- Transmission defaults to standard automatic mode
- Gear indicator on the dashboard may flash or fail to show manual gears
- Harsh or delayed shifting in some vehicles as a fail-safe response
Likely causes
- Faulty auto shift manual mode switch (gear selector switch or paddle shifter)
- Wiring harness damage causing a short to ground in the manual shift circuit
- Corroded, loose, or damaged electrical connectors in the shift circuit
- Spilled liquid on the center console damaging the shifter assembly
- Faulty Transmission Control Module (TCM) or Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Inspect the center console and shifter assembly for signs of liquid spills or physical damage.
Look for: Sticky residue, corrosion, or damaged wiring near the shifter mechanism that could cause a short circuit.
Check the wiring harness and connectors associated with the auto shift manual mode circuit.
Look for: Chafed wires, exposed copper, bent pins, or corrosion that would cause a short to ground or poor connection.
Use a digital multimeter to test the voltage at the auto shift manual mode switch connector.
Look for: Voltage readings that are significantly lower than the manufacturer's specified reference voltage (often 5V or 12V), indicating a short to ground or supply issue.
Test the continuity and resistance of the auto shift manual mode switch itself while toggling it.
Look for: Infinite resistance (open) or zero resistance (short) when the switch is activated, indicating internal failure of the switch.
Check the circuit integrity between the shifter switch and the TCM/PCM.
Look for: High resistance or a short to ground in the wiring between the switch and the control module, isolating the issue to the harness rather than the components.
This page explains the generic P0957 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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