Auto Shift Manual Mode Circuit Range/Performance
The P0956 code indicates that the Powertrain Control Module (PCM) has detected a malfunction in the manual mode circuit of the automatic transmission. This circuit allows the driver to manually select gears using the shift lever or paddles. The PCM monitors voltage and resistance in the circuit; when these values fall outside the expected range, the code is set. This can be caused by a faulty shift solenoid, damaged wiring, or a defective transmission control module.
01. Most Common Causes
- Faulty manual mode shift solenoid
- Damaged wiring or connectors in the manual mode circuit
- Defective transmission control module (TCM)
02. Symptoms You Will Notice
- Transmission stuck in automatic mode
- Inability to manually shift gears
- Check Engine Light illuminated
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the wiring and connectors related to the manual mode circuit for damage or corrosion.
Step 3: Test the manual mode shift solenoid resistance with a multimeter and compare to manufacturer specifications.
Step 4: If wiring and solenoid are okay, test the TCM for proper operation or reprogram if necessary.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe to drive, but you will lose manual shift capability. The transmission will default to automatic mode. However, if other symptoms like harsh shifting occur, have it inspected promptly.
How much does it cost to fix?▼
Repair costs vary. Simple wiring repairs may cost $50-$150, while replacing a shift solenoid or TCM can range from $200-$600 or more, including labor.