Transmission Mode Switch Circuit High
The P071F 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 shift lever assembly, tells the PCM which gear position (P, R, N, D) is selected. A high circuit voltage typically means a short to power, a faulty switch, or a wiring issue. This can cause incorrect gear selection, harsh shifting, or transmission defaulting to a safe mode.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission stuck in one gear or limp mode
- Incorrect gear display on dashboard
- Harsh or delayed shifting
- Vehicle may not start or shift out of Park
2. Most Common Causes
- Faulty transmission mode switch
- Short to power in the switch circuit
- Damaged wiring or connector
- Corroded terminals
- Faulty PCM (rare)
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P071F and check for other related codes.
Step 2: Visually inspect the transmission mode switch and wiring for damage, corrosion, or loose connections.
Step 3: Test the switch circuit voltage with a multimeter; compare to manufacturer specifications.
Step 4: Check for shorts to power or ground in the wiring harness.
Step 5: If wiring is okay, replace the transmission mode switch.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The transmission may enter limp mode, limiting speed and causing unsafe driving conditions. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and switch replacement, but costs vary by vehicle and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.