Auto Shift Manual Mode Circuit Malfunction
The P0955 code indicates a problem in the manual shift mode circuit of an automatic transmission. This circuit allows the driver to manually select gears via the shift lever or paddles. The Powertrain Control Module (PCM) detects an electrical fault, such as an open, short, or incorrect voltage in the circuit, preventing proper manual shift operation.
01. Most Common Causes
- Faulty manual shift mode switch
- Damaged wiring or connectors in the manual shift circuit
- Corroded or loose electrical connections
- Failed PCM (rare)
02. Symptoms You Will Notice
- Inability to manually shift gears
- Transmission stuck in automatic mode
- Check Engine Light illuminated
- Transmission may default to a limp mode
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and verify P0955 is present.
Step 2: Inspect the manual shift mode switch and its wiring for damage or corrosion.
Step 3: Test the circuit continuity and voltage using a multimeter.
Step 4: Check for TSBs related to the vehicle model.
Step 5: If wiring is intact, replace the manual shift mode switch.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive, but manual shifting will be unavailable. If the transmission enters limp mode, avoid high speeds and get it inspected soon.
How much does it cost to fix?▼
Typically $150-$400, including parts and labor. The switch itself costs $50-$150, plus diagnostic time.