Transmission Mode Switch Circuit High
The P071C code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the transmission mode switch circuit. This switch, often part of the manual shift or sport mode system, sends a signal to the PCM to select different shift patterns. A high voltage reading suggests a short to power, a faulty switch, or a wiring issue. This can cause erratic shifting, limp mode, or inability to select certain transmission modes.
01. Most Common Causes
- Faulty transmission mode switch
- Short to power in the switch circuit
- Damaged wiring or connector
- Corrosion or poor ground connection
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission stuck in limp mode
- Inability to select manual or sport mode
- Harsh or delayed shifts
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the transmission mode switch and wiring for damage or corrosion.
Step 3: Test the switch resistance and voltage with a multimeter; compare to manufacturer specs.
Step 4: Check for shorts to power or ground in the circuit; repair as needed.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the transmission may enter limp mode, reducing performance and potentially causing further damage.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for parts and labor, depending on the cause and vehicle model.