Auto Shift Manual Control Circuit High Voltage
The P0953 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the auto shift manual control circuit. This circuit is responsible for communicating the driver's manual shift commands (e.g., up/down shifts) from the shift lever or steering wheel paddles to the transmission control module. A high voltage reading typically suggests a short to power, a faulty sensor, or a wiring issue. This can prevent the transmission from responding to manual shift inputs, potentially causing erratic shifting or loss of manual mode functionality.
01. Most Common Causes
- Short to battery voltage in the manual shift control circuit wiring
- Faulty manual shift switch or sensor
- Damaged connector or corroded terminals
- Faulty PCM or TCM (less common)
02. Symptoms You Will Notice
- Transmission stuck in automatic mode, unable to shift manually
- Check Engine Light illuminated
- Erratic or delayed shifting when using manual mode
- Transmission may default to a safe mode (limp mode)
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes (e.g., P0951, P0952).
Step 2: Visually inspect the wiring and connectors for the manual shift control circuit for damage, corrosion, or shorts.
Step 3: Test the manual shift switch/sensor resistance and voltage with a multimeter; compare to manufacturer specs.
Step 4: Check for a short to power by disconnecting the sensor and measuring voltage at the circuit; if voltage is present, repair the short.
Step 5: If all else is normal, suspect a faulty PCM/TCM and perform a software update or replacement.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive with this code, as it may cause unpredictable transmission behavior. The transmission may enter limp mode, limiting speed and drivability. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost varies depending on the cause. Simple wiring repairs can cost $100-$200, while replacing a shift switch or sensor may be $150-$300. PCM replacement can exceed $500.