What it means
The auto-shift manual mode circuit reports a high condition. Manual mode shift requests cannot be reliably interpreted.
At a glance
- Usually lights the check-engine light
How it works
A manual-mode switch or position sensor signals the automatic transmission when the driver requests an upshift or downshift. The transmission control module monitors the circuit level as the selector moves. P0958 sets when the signal is higher than expected, such as from a short to battery voltage or a switch that stays open.
Common causes
Most likely first.
- Wire shorted to B+
- Switch stuck open
- 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 circuit reads active when the selector is not requesting a shift.
- Move the selector through manual mode and observe whether the input changes between the expected states.
- Inspect the switch or sensor connector and harness for damaged insulation, wires contacting a power feed, corrosion, or loose terminals.
- Following the manufacturer's circuit isolation procedure, check for a short to battery voltage and test whether the switch remains open when it should change state.
- If the signal is correct at the switch but high at the transmission control module, test the circuit wiring and connectors between them.
Common fixes
- Clean and secure the manual-mode switch or sensor connector.
- Repair wiring shorted to a power feed.
- Replace a switch that remains open or fails to change state with selector movement.
- Clear the code and confirm live manual-mode data responds correctly to upshift and downshift requests.
Can I keep driving?
If normal drive operation and shifting remain reliable, limit driving to necessary trips and avoid manual mode. Stop if the vehicle slips, shifts harshly, or loses predictable gear changes, as ongoing transmission stress can worsen damage.
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.